JPS636148B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a semiconductor evaporative cooling device, and particularly to a semiconductor evaporative cooling device that cools a semiconductor by utilizing a phase change between a liquid phase and a gas phase of a condensable cooling medium, and includes a snubber circuit. This invention relates to a semiconductor boiling cooling device.

Generally, a semiconductor boiling cooling device is constructed by housing a semiconductor in a sealed container and enclosing a condensable refrigerant such as Freon R113 so as to immerse the semiconductor. Therefore, when the semiconductor generates heat due to energization, the condensable refrigerant boils and changes its phase from the liquid phase to the gas phase, and at this time, the semiconductor is cooled by taking latent heat from the heat generating semiconductor. In addition, a condenser is installed at the top of the sealed container, and the vapor phase refrigerant that undergoes a phase change and vaporizes within the sealed container flows into the condenser and releases latent heat to the air outside the condenser. As a result, the gas phase refrigerant is condensed and liquefied to become a liquid phase refrigerant, which returns to the sealed container again.

In this way, the condensable refrigerant circulates between the sealed container and the condenser due to the phase change between the liquid phase and the gas phase.
Heat generated in a semiconductor housed in a sealed container is efficiently transferred to a condenser to cool the semiconductor.

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

A conventional semiconductor evaporative cooling device is constructed as described above, and an example of this construction, particularly its snubber circuit, is shown in FIG. 1 of the accompanying drawings.

In the figure, numeral 1 is a semiconductor such as a thyristor, gate turn-off thyristor (GTO thyristor), or diode; 2, 3, and 4 are components that constitute a snubber circuit; numeral 2 is a capacitor; 3 is a diode; and 4 is a resistor. show.

Now, semiconductor 1 turns on the DC high voltage and large current circuit.
In the case of a semiconductor to be OFF-controlled, for example, a GTO thyristor, when a high-speed switching operation is performed, an abnormal voltage is generated across the semiconductor 1, and when this abnormal voltage exceeds the allowable voltage of the semiconductor 1, the semiconductor 1 destroys. Therefore, in order to absorb the abnormal voltage generated across the semiconductor, a snubber circuit is connected in parallel to the semiconductor 1 as shown in FIG.
It is preferable that the wiring constituting the closed circuit formed by the capacitor 2, diode 3, and semiconductor 1 be as short as possible. If the wiring of this snubber circuit is 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 the conventional semiconductor boiling cooling device, as shown in FIG. 2 of the attached drawings, the sealed container 10
The components of the snubber circuit, that is, the capacitor 2, the diode 3, and the resistor 4, are all installed outside the sealed container 1, and are installed in an airtight bushing provided on the wall of the sealed container 1. 11, the semiconductor 1 and the snubber circuit component 2
~4 and conductors (wiring) 12, 13a, 13b, 1
3c, there is a natural limit to how short the wiring length can be, and as a result, the surge voltage absorption effect of the semiconductor 1 cannot be sufficiently obtained.

This will be described in detail below based on FIG. 2 showing the configuration of a conventional device.

In the figure, 10 is a transport container, 11 is an airtight bushing, 12, 13a, 13b, 13c are wiring conductors, 14 is a condenser, and 14a is a condenser 14.
15 is a sealed container 10
A vapor pipe 17 is for guiding the gaseous refrigerant 16 generated within the container to the condenser 14, and a liquid pipe 17 is for returning the liquid refrigerant 18 condensed in the condenser 14 to the sealed container 10. Also,
The semiconductor 1 and a liquid-phase condensable refrigerant 18 are sealed in the sealed container 10, and a predetermined amount of the liquid-phase refrigerant 18 is sealed so that the semiconductor 1 is sufficiently immersed in the liquid-phase refrigerant 18. Further, the upper space of the sealed container 10 and the inside of the condenser 14 are configured to be filled with the gas phase refrigerant 16 without mixing with non-condensable gas such as air.

Further, an airtight bushing 11 is disposed on the wall of the sealed container 10 and is electrically connected to the semiconductor 1 stored in the sealed container 10 by a conductor 12. Furthermore, a snubber circuit is provided. A capacitor 2, a diode 3, a resistor 4, and an airtight bushing 11 are connected to each other by conductors 13a, 13b, and 13c.

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, the liquid phase refrigerant 18 that is in contact with the semiconductor 1 boils and undergoes phase conversion from the liquid phase to the gas phase. At this time, latent heat is taken away from the semiconductor 1, so the semiconductor 1 is cooled. On the other hand, the phase-changed gas phase refrigerant 16 rises upward due to the density difference and is led to the condenser 15 through the steam pipe 15. Since the outside of the many finch tubes 14a of the condenser 14 is cooled by air, the gas phase refrigerant 16 releases latent heat inside the condenser 14, condenses and liquefies, and the liquid phase refrigerant 18 becomes. This liquid phase refrigerant 1
8 returns to the sealed container 10 through the liquid pipe 17 due to the action of gravity, and cools the semiconductor 1 again.

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

In this way, in conventional devices, semiconductor 1
is built in the sealed container 10, and the snubber circuit consisting of the capacitor 2, diode 3, and resistor 4 is installed outside the sealed container 10. , had to be connected by long wiring of conductors 13a, 13b, and 13c.

However, in the snubber circuit, diode 3,
The closed circuit formed by the capacitor 2 and the semiconductor 1 particularly needs to have a small inductance, but in the conventional device as described above, the semiconductor 1 - conductor 12 - hermetic bushing 11 -
Since a snubber circuit is formed by the wiring path of conductor 13a - diode 3 - conductor 13b - capacitor 2 - conductor 13c - hermetic bushing 11 - conductor 12 - semiconductor 1, no matter how short the wiring is made, inductance can be reduced. However, there are limits to this, and the drawback is that a sufficient surge voltage absorption effect cannot be obtained.

In order to improve the drawbacks of the conventional device, as shown in FIG. 3 of the accompanying drawings, a diode 3 and a capacitor 2 are housed together with a semiconductor 1 in a sealed container 10, and conductors 13a', 2 are connected between these components.
A method of wiring using 13b' and 13c' can be considered. Note that the resistor 4 is installed outside the container 10 and wired through an airtight bushing 11 as shown in the figure. According to such a method, the diode 3 and the capacitor 2 can be wired close to the semiconductor 1, so that the wiring inductance is reduced and the surge voltage absorption effect is certainly increased. However, on the other hand, this method has the following drawbacks. In other words, (1) The material constituting the capacitor element is a plastic film or paper as a dielectric, and the electrodes are made by depositing metal such as zinc on the dielectric, or are made of ultra-thin aluminum foil. used. These materials contain refrigerants such as Freon R113
If it comes into contact with it, it will corrode and the electrical properties of the capacitor will deteriorate significantly. Therefore, when a capacitor is housed in a sealed container, the capacitor element is housed in a metal case, and insulating oil is filled in as a coolant. A so-called oil-filled capacitor must be used. In such oil-filled capacitors, the capacitor element is usually placed inside a metal case with one end open, 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. It is manufactured by

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, refrigerant such as fluorocarbons Because of this, there is a risk that the capacitor element will deteriorate due to corrosion, so 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 150 x 100 x 50 mm rectangular parallelepiped), welding the metal case and top plate requires high heat generated during welding. 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 make the capacitor significantly larger and would be very uneconomical. The design is

(2) Since capacitor elements are usually made of dielectric material such as paper or plastic, the maximum allowable temperature of the element is relatively low at 75 to 85°C. On the other hand, the permissible temperature for semiconductors is 125-150
℃, 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 surface temperature of the capacitor case will be 70 to 75 degrees Celsius, which is the refrigerant temperature.Furthermore, due to the heat generated by the capacitor itself, the element center temperature will be higher than the refrigerant temperature in the case, and the temperature of the capacitor will increase. This will exceed the permissible temperature. Therefore, if the center temperature of the condenser element is to be lower than the allowable temperature, the refrigerant temperature must be set low, which requires a larger condenser, which increases the size of the semiconductor evaporative cooling system itself. Therefore, the weight increases and the device becomes extremely uneconomical.

(3) When a condenser is placed in a sealed container, the sealed container becomes larger, and in conjunction with the larger condenser described in item 2 above, the semiconductor boiling cooling device becomes even larger. Further, when the evaporative cooling device uses Freon R-113 as the refrigerant, when the refrigerant temperature exceeds 47°C, the pressure inside the sealed container becomes higher than the outside pressure. Therefore, boiling cooling equipment is subject to pressure vessel regulations under the Industrial Safety and Health Act, but equipment that does not contain a condenser in a sealed container is
Although the container has a small internal volume and is not subject to regulations as a pressure vessel, and falls within the range of so-called simple containers, by storing a capacitor, etc. in a sealed container, the internal volume of the sealed container increases and the pressure increases. It will be regulated as a container. When pressure vessels are regulated in this manner, inspection duties become obligatory, which results in a longer manufacturing period and an increase in manufacturing cost as well as an increase in manufacturing man-hours.

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

The present invention improves the drawbacks of the conventional device described above, and further reduces the wiring inductance by shortening the wiring length between the semiconductor 1 and the snubber circuit,
The object of the present invention is to provide a suitable semiconductor evaporative cooling device that improves the surge voltage absorption effect.

In order to achieve this object, the present invention provides an airtight bushing to be connected to the semiconductor on a wall portion of the sealed container close to the semiconductor, and a snubber close to the outside of the wall portion of the sealed container where the airtight bushing is installed. A circuit capacitor is installed, the terminals of the capacitor are directly connected to the airtight bushing, and the semiconductor inside the sealed container is wired to the capacitor outside the sealed container to form a snubber circuit. It is characterized by this.

Hereinafter, an embodiment of the present invention will be described based on FIG. 4 of the accompanying drawings.

In the figure, a semiconductor 1 and a snubber diode 3 are housed in a sealed container 10, and a liquid phase refrigerant 18 is also filled. An airtight bushing 11 is provided on the wall of the sealed container 10, and this airtight bushing 11
and a terminal of the semiconductor 1 are connected by a conductor 12.

On the other hand, airtight bushings 21a and 21b connected to the semiconductor 1 are provided on the wall of the sealed container 10 near the terminals A and B of the semiconductor 1, and the airtight bushings 21b and the B terminal of the semiconductor 1 are connected by a conductor 22b. The A terminal of the semiconductor 1 and the hermetic bushing 21a are connected via the diode 3 by a conductor 22a. Moreover, the airtight bushing 21a,
21b, a snubber capacitor 2 is provided on the wall of the sealed container 10 via a heat insulating material 23, and the terminal conductors 2D and 2 of this capacitor 2
E and the airtight bushings 21a, 21b are directly connected, and this connection is made by soldering or screwing. The capacitor 2 can be classified into a foil electrode type and a metal vapor deposition type, as shown in FIG. 5 of the accompanying drawings, depending on the structure of the electrodes.

Further, the reason why the heat insulating material 23 is interposed between the wall of the sealed container 10 and the capacitor 2 is that when the capacitor 2 is brought into close contact with the sealed container 10, the sealed container 10
To prevent the temperature of the liquid phase refrigerant 18 from being thermally conducted to the condenser 2 through the wall of the
A heat insulating material 23 is provided between the sealed container 10 and the capacitor 2.
This is because it is desirable to install and insulate.

Incidentally, the snubber resistor 4 is installed outside the sealed container 10, and is wire-connected between the airtight bushings 11 and 21a by a conductor 24.

Since the semiconductor evaporative cooling device of the present invention, particularly its snubber circuit, is configured as described above, it has the following characteristics or effects.

(1) Airtight bushings 21a, 21b are provided near the terminals A and B of the semiconductor 1, and the airtight bushings 21a, 21b are provided outside the sealed container 10.
Connect the terminal conductors 2D and 2E of capacitor 2 directly to 1b.
As a result, the wiring length between the semiconductor 1 and diode 3 arranged inside the sealed container 10 and the capacitor 2 provided outside the sealed container 10 becomes extremely short, and therefore the wiring inductance is reduced. This greatly increases the surge voltage absorption effect in the snubber circuit.

(2) Since the capacitor 2 is attached to the outer wall of the sealed container 10 via the heat insulating material 23, the sealed container 1
Since the influence of heat from the refrigerant inside the capacitor 2 is small, and the heat generated by the capacitor 2 itself is dissipated to the outside air from exposed surfaces other than the capacitor mounting surface, the temperature is lowered and reliability is improved.

(3) Since the capacitor 2 has a terminal conductor connected to the end face of the electrode by a method such as direct soldering, it is possible to manufacture the capacitor itself with a small inductance. In conventional capacitor elements, the capacitor element is housed in a metal case, and the bushing provided in the metal case and the capacitor element are connected using flexible lead wires, so the cross-sectional area of the lead wires is relatively thin.
Furthermore, since the lead wire is point-connected to a part of the electrode end surface by a method such as soldering, the inductance between the bushing and the element is relatively large. In this case, a metal case is not used, bushing is not required, and the plate-shaped terminal conductor from the capacitor element is connected directly to the electrode end surface of the capacitor element, so that the terminal conductor on the electrode end surface is The connection area can be made much larger than conventional ones. The large connection area between the terminal conductor and the end face of the electrode means that since the electrode is configured by winding, power is supplied directly from the terminal conductor to each part of the electrode, which reduces inductance. become.

(4) 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. Therefore, the manufacturing period is shortened. Moreover, economical production becomes possible.

(5) In the event that the capacitor 2 breaks down, the method shown in Figure 3 involves opening the sealed container, replacing or repairing the capacitor stored inside, and then resealing the container.
Although the refrigerant must be injected under vacuum, the device of the present invention does not require opening the sealed container, and the terminal conductor 2 of the capacitor 2 can be directly injected into the terminal conductor 2 of the capacitor 2.
By disconnecting D, 2E from the airtight bushings 21a, 21b, the capacitor 2 can be easily replaced, thereby shortening the repair period and significantly reducing the repair cost.

As described above, the semiconductor evaporative cooling device of the present invention has many features and has the effect of being extremely practical and effective.

In the embodiment shown in FIG. 4, the capacitor 2 is disposed below the sealed container 10.
If the snubber circuit wiring can be shortened,
The diode 3 may be placed in any direction in the sealed container 10, and although the case where the diode 3 is housed in the sealed container 10 is shown, it is not necessary to place it inside the sealed container either, and it may be placed outside the sealed container. There is no problem. Furthermore, the resistor 4 may be housed in the sealed container 10.

[Brief explanation of the drawing]

Fig. 1 is a circuit configuration diagram showing an example of a semiconductor and snubber circuit, Fig. 2 is a vertical cross-sectional explanatory diagram showing the structure of a conventional semiconductor evaporative cooling device, and Fig. 3 is a method for improving the drawbacks of the conventional device. FIG. 4 is an explanatory longitudinal sectional view showing an embodiment of the semiconductor evaporative cooling device of the present invention, and FIG. 5 is a longitudinal sectional view of a foil electrode type capacitor. 1... Semiconductor, 2... Capacitor, 3... Diode, 4... Resistor, 10... Sealed container, 1
1, 21a, 21b...airtight bushing, 12,
13a, 13b, 13c, 13a', 13b', 13
c', 17, 22a, 22b... Conductor, 14... Condenser, 16... Gas phase refrigerant, 18... Liquid phase refrigerant, 2
3...Insulation material. In each figure, the same reference numerals indicate the same or equivalent parts.

Claims (1)

[Scope of Claims] 1. Heat generated in the semiconductor is condensed by using a phase change between a liquid phase and a gas phase of the cooling medium, which is stored in a semiconductor immersed in a cooling medium sealed in a sealed container. In a semiconductor boiling cooling device which performs cooling by transferring heat to a container and is equipped with a snubber circuit, an airtight bushing connected to the semiconductor is provided on a wall portion of the sealed container close to the semiconductor;
A snubber circuit capacitor is installed close to the outside of the wall where the airtight bushing is installed in the sealed container,
Semiconductor boiling cooling characterized in that the terminal of the capacitor is directly connected to the airtight bushing, and the semiconductor inside the sealed container and the capacitor outside the sealed container are wire-connected to form a snubber circuit. Device. 2 The snubber circuit capacitor installed close to the outside of the wall of the airtight bushing of the sealed container is
The semiconductor boiling cooling device according to claim 1, wherein the semiconductor boiling cooling device is installed with a heat insulating material interposed between the wall portion and the wall portion.