SU682970A1 - Cooler - Google Patents

Description

3

mounting surfaces for fastening the tools-: The casing with plates can consist of two parts rigidly fixed one relative to the other. Between the plates and parts of the casing in contact with them can be laid a foil of soft metal, such as annealed copper.

For the purpose of galvanic isolation of semiconductor devices, a strip of insulating material, such as beryllium oxide, can be placed between the plates and the parts of the housing in contact with them. FIG. 1 shows the proposed cooler in section along with the semiconductor device of the pin type; in fig. 2 - the same, plan view with the instrument; in fig. 3 shows another embodiment of the cooler: with a casing consisting of two parts, in an isometric view.

The cooler (Fig. 1) contains a base 1 with an assembly surface 2 and a threaded hole 3. On the base 1, perpendicular to its longitudinal axis 4, air-cooled plates 5 are installed with a clearance, which are, for example, cold-pressed. The axes of the holes 6 and 7 of the adjacent plates are shifted by a distance equal to half the pitch between the holes. The top plate 8 carries the mechanical load and has three tabs 9 with slots 10 for the cooler to cool. The pin And of the device 12 is screwed into the threaded hole 3 of the base 1, pressing the semiconductor device 12 with the end surface 13 to the mounting surface 2 of the base 1 through the copper plate 14 having the hole 15 for current collection. The gap 16 between the plates 5 is a quarter of the diameter of the holes 6 and 7. Along the perimeter, the walls 17 surround the plates 5 and are spaced from them at a distance equal to the gap between the plates. These walls 17 form a casing which, together with the plates 5, constitutes the air channel 18. Moving inside the channel 18 parallel to the axis 4, the cooling air passes through all the plates 5 and the plate 8, washing also the peripheral edges 19 of the plates 5.

The direction of air inlet and outlet of the cooler is shown by arrows.

Such a structure is easy to manufacture, since it consists of a base of the simplest form and plates with holes that can be made by simple stamping; it allows the use of any materials, including cheap and light aluminum alloys, as well as the use of plates of very small thickness (1 mm or less) and install them with any gaps between them.

Cold pressing ensures reliable thermal contact with the base and cooling plates. Square edge with central exit 4

This is best in terms of edge efficiency.

FIG. 3 presents the second option

constructive implementation of the chiller

5 unassembled, designed for

cooling single semiconductor

device.

The cooler consists of two parts (top and bottom), inserted into each other. K) Each of them does not include a single casting; it contains a base 1 with a mounting surface 2 for heeling the device, plates 5 with holes 6 and 7 and a side wall 17. The base 1 of the upper part with mounting 15 is made thicker than the base bottom part where there is no mounting surface. In the base 1 of the upper part there are names 20 and 21, into which are extended upper edges 22 and 23 of the lower part, which ensure fixation of the parts relative to each other, and a pin is inserted into the hole 24 located on the mounting surface 2 pills noluprovodnikovogo device. parts to each other are provided either simultaneously with the semiconductor device or independently of it. The assembled base 1 and side 0 walls 17 of both parts form a casing. The gap 16 between the plates of one part is equal to the thickness of the plate 5 plus the double gap between the adjacent plates of the cooler when assembled.

5 In the course of operation, the air moving inside the casing passes through all the openings of the plates 5 in the direction perpendicular to their planes.

The design of the cooler makes it possible to mount the fixtures on all four or even six sides. For this, the casing should have additional mounting surfaces on four faces (for example, in a circuit with a common cathode), and in the case of mounting the instruments on six sides, the outer plates (for example, in the upper part) should have mounting surfaces in addition to the air cooling holes. and be thicker. 0 The design allows for mass production to apply casting, while the metal mold for each part of the cooler must contain a rack with rods that provide perforations in the plates. 5 Each of FIG. 1 and 3 design options can be used to cool both tablet and pin types.

The proposed chiller at high heat removal efficiency per surface unit allows to reduce the gaps between the cooling plates to very small areas. This in itself provides the cooler with small dimensions and, what is more, allows maximum heat transfer surfaces to the heat source and due to this use plates of rather small thickness (1 mm or less), sufficiently high efficiency of the edge, which in turn , significantly reduces the size of the cooler and its weight.

From the point of view of cooler compactness, the smaller the gap between the cooling plates, the better. However, there is a limit, less than which to choose the specified gap does not make sense.

It is known that, from the point of view of cooling efficiency, the determining factor in choosing the design parameters of a cooler is the ratio of the heat transfer coefficient to the aerodynamic drag coefficient,

Studies show that with a corridor arrangement of cooling air holes, this ratio increases with a decrease in the interplate gap, reaching a maximum at a gap of approximately one quarter of the diameter of the holes. Further reduction of the gap leads to a decrease in this ratio, since the air flow in this case is more and more approaching the flow in a smooth pipe.

For chesspieces with a staggered arrangement of holes, when air from the holes of one plate hits the continuous wall KV of the adjacent plate at a right angle, the heat transfer coefficient varies very little with the interplate gap. The aerodynamic resistance in this case is mainly due to the losses due to sudden constriction and sudden expansion in the openings of the plates. These losses fall with a decrease in the gap and reach a minimum when the gap is equal to one quarter of the diameter of the holes, when the velocity of the air in the gap of the holes is compared to the velocity of the air in the holes. Further reduction of the gap leads to a sharp increase in losses, since the air velocity in the gaps begins to prevail over the air velocity in the holes.

Thus, as with the corridor and the staggered arrangement of the holes in the plates, the minimum interplate gap should be equal to or slightly less than one-quarter of the hole diameter (i.e., 0.2), especially since further reduction of the gap does not lead to significant reduce the size of the cooler.

The actual gaps between the plates will be determined by the manufacturing technology of the cooler. In addition, for chillers operating in a very dusty atmosphere, large gaps may be required.

From the foregoing it follows that in the coolers the gap between the plates should be in the range of 0.2 to 1 the diameter of the holes in the plates. At the same time, if possible, one should strive for smaller gap values.

Due to good heat transfer and sufficient heat removal surface, the outer edges of the cooling plates can make a significant contribution to the heat removal process, and therefore it is advisable to position the casing relative to these edges with a certain gap. This gap should be sufficient to pass the desired air flow. However, as calculations show, it should not exceed double

the distance between the cooling plates, since this does not lead to a real increase in the power of heat removal, but increases the cost of pumping cooling air.

In terms of its technical and economic indicators, this cooler considerably surpasses both standard finned coolers and the well-known perforated cooler. And this superiority

it manifests itself not only in weight and dimension indicators, but also in the power consumption for pumping cooling air. In such coolers, effective heat removal is carried out at low speeds and

cooling air flow, and therefore, despite the considerable resistance of the perforated plates, the pumping power remains low. Comparative data proposed

design of the cooler and the known structures of the following; ie: the cooler made according to the first constructive variant with the same power of the heat sink of 330 W with the typical A-7 cooler, 4.2 times

lighter and 5.6 times more compact. At the same time, the power for pumping cooling air is 1.8 times less.

The cooler designed according to the second variant, with the same heat removal capacity with a typical cooler for the T9-200 thyristor, is 4.16 times lighter and 5.7 times more compact with correspondingly smaller (1.17 times) cooling costs.

In a circuit with a common cathode, the weight T1 dimensions can be further reduced if each cooler, made according to the second constructive option, is used to cool several semiconductor devices pressed, for example, by anodes, to four or even of the edges of its faces. Such a cooling system will be especially compact for powerful devices (for example, T-500), when it is necessary to cool both the anode and the cathode. In this case, to cool the cathodes, it is advisable to use a cooler made in accordance with the first constructive variant.

In addition, from late on pill-type devices, an acute need

Most important in creating powerful coolers for heat removal of 500-800 W and more. Attempts to create such coolers on the usual well-known principle were unsuccessful, since an increase in the size of coolers with existing small values of the contact surfaces of tablet devices led to a sharp drop in the efficiency of the fin due to the forced distance of the cooling surfaces from the heat source.

The cooler according to the present invention, due to the advantages listed above, can be created at very high heat removal rates with high cooling efficiency. Thus, according to the first constructive variant, the cooler, designed for 800 Üt of output power, at the temperature of the case of a tablet semiconductor device at 85 ° C and with the ventilation power consumption of 26 W was 1.5 times lighter and 1.5 times smaller than the typical dimensions cooler A-7, whose power output is only 330 watts.

The ability to create compact coolers for an exhaust heat capacity of the order of 1 kW makes it possible to refuse water coolers in the specified power range, which will simplify the design and increase the reliability of devices containing power semiconductors.

Claims (7)

Invention Formula I. Cooler, for example, for semiconductor devices, containing air-cooled plates with holes and mounting surfaces for fastening, in order to increase cooling efficiency while reducing weight and size a cooler, each mounting surface is associated with a set of plates enclosed around the perimeter of the casing so that the air flow is directed perpendicular to their planes, and the gap between the plates is equal to 0.2-1 of the diameter of the holes in them. 2. A cooler according to claim 1, characterized in that the axes of the holes in the adjacent plates are displaced one relative to another a distance equal to half the pitch between the holes. 3. Coolant on PP. I and 2, which is also distinguished by the fact that the casing walls are spaced from the edges of the plates for a distance less than double gap between the plates. 4. Coolant on PP. 1 and 2, characterized in that the casing is connected by thermal contact with a set of plates and has additional mounting surfaces for fastening devices. 5. Coolant on PP. 1, 2 and 4, about tl and h ay u and, with the fact that the casing with the plates consists of two parts, rigidly fixed one relative to the other. 6. Cooler on PP. 1, 2, 4 and 5, from which the foil of soft metal, for example annealed copper, is laid between the plates and the parts in contact with them. 7. Cooler on PP. 1, 2, 4, and 5, which is due to the fact that, for the purpose of galvanic isolation of semiconductor devices, a strip of insulating material, such as beryllium oxide, is laid between the plates and the parts of the housing in contact with them. Sources of information taken into account in the examination 1.Aksenov A.I. “Heat removal in semiconductor devices. M., "Energie, 1971, with. 140-146. 2. The patent of Germany N ° 1276209, cl. 21 g 11/02, I97I.