RU53072U1 - DEVICE FOR COOLING AND THERMOSTATING SEMICONDUCTOR DEVICES - Google Patents

Abstract

The utility model relates to electrical engineering, namely to converting technology, and can be used for efficient cooling and temperature control of power semiconductor devices (SPP), in particular, modular assemblies of pulse thyristors having a flat contact surface. In the device for cooling and thermostating semiconductor devices made in the form of an assembly of heat pipes (TT) with fins, having an evaporation zone and a condensation zone, and cooled elements located between the pipes with thermal contact, the heat pipes are made on the basis of a profile equipped with an internal capillary axially grooved structure. The external fins of the TT are formed with the formation of parallel contact surfaces in the evaporation zone, and the heat pipe outside the evaporation zone is bent so that the condensation zone of the heat pipes is located above the heat contact zone. The evaporation zone can be located in the center of the heat pipe profile with the formation of two symmetric condensation zones. The inventive device provides the possibility of air cooling of power semiconductor devices in the conditions of packet-pulse loading and overall limitations. This design has greater compactness and simplicity compared to the prototype due to the use of a serial profile, is more simple in technological design and less material intensive. The use of a homogeneous profile material compatible with the coolant eliminates the appearance of corrosion and increases the resource.

Description

The utility model relates to electrical engineering, namely to converting technology, and can be used for efficient cooling and temperature control of power semiconductor devices (SPP), in particular, modular assemblies of pulsed thyristors having a flat contact surface.

A device is known for cooling an SPP like a two-phase thermosiphon, comprising a housing from a section of a pressed profile with external fins, internal vertical condensation channels and a steam pipe. In the lower part of the internal vertical channel-steam pipe (in the boiling zone), an evaporator finned with straight rings is located, to the end surfaces of which one or two SPP are pressed. The condensation channels and the steam channel above are connected by a steam collector, and below the condensate collector. The lower part of the channel is the steam pipe (boiling zone) and partially the lower parts of the condensation channels are filled with a liquid intermediate coolant (RF Patent No. 2201014, on. 20.03.2000, IPC ⁷ N 01 L 23/34, 23/36. Device for cooling power semiconductor devices )

This technical solution is aimed at solving the problem of cooling single semiconductor devices, for example, powerful transistors operating in static mode. The known design has large dimensions, is difficult in technological and constructive design, is material-intensive, expensive and

not intended for cooling semiconductor devices operating in a pulsed mode, such as thyristor modules.

The closest technical solution to the claimed utility model is a device for cooling and thermostating SPP, based on heat pipes (TT) having an evaporation zone and a condensation zone. The cooled elements are placed between the heat pipes to ensure thermal contact between them. The heat pipe is a hollow copper casing, the capillary structure of powdered copper is baked to the inner surface of which. The capillary structure of the TT is filled with water. The outer surface of the TT is equipped with screw or plate finning made of deformable aluminum (Sheleg V.K., Mazyuk V.V. Calculation of the transport capacity of powder capillary structures of heat pipes taking into account drainage. // Heat pipes: theory and practice: Materials of the International Seminar School, Part 1 - Minsk: ITMO named after A.V. Lykov. AN BSSR, 1990, p. 106 -112).

The disadvantage of this design is its large dimensions and the associated problems that arise when placing thyristor modules in an instrument power rack, which has limited dimensions. For example, the inability to provide the necessary clearance between adjacent CTs can cause electrical breakdown during operation of the thyristor module. In addition, this device is quite difficult to perform due to the large number of technological operations, and the presence of dissimilar materials, such as copper and aluminum, causes the occurrence of electrochemical corrosion, which negatively affects the service life.

The authors were faced with the task of reducing the dimensions of the device for working conditions with free convection in the air and the limited dimensions of the instrument racks, as well as increasing its service life and reliability.

The problem is achieved in that in the device for cooling and thermostating semiconductor devices, made in the form of an assembly of heat pipes with fins having an evaporation zone and a condensation zone, and cooled elements located between the pipes with providing thermal contact, the heat pipes are made on the basis of the profile, equipped with an internal capillary structure in the form of axially spaced grooves, the outer ribbing is formed with the formation of parallel contact surfaces in the evaporation zone, and eplovaya tube evaporation zone is curved so that the condensation zone of the heat pipes is located above the thermal contact area.

In the inventive device, the evaporation zone can be located in the center of the heat pipe profile with the formation of two symmetric condensation zones located relative to the evaporation zone (heat contact zone) at an angle α = 5-50 °, which is optimal and ensures the most efficient operation of the CT.

The bending angle of the heat pipes in the assembly may increase from the lower heat pipe to the upper. This layout of the assembly "SPP - TT" increases the heat removal by improving the conditions of free convection.

Depending on the external conditions, in order to improve the heat transfer, the CTs in the assembly can be parallel to each other or be offset in the horizontal plane relative to each other by an angle P = 180 / p, where n is the number of elements to be cooled.

To increase the heat removal from the cooling device by increasing the area of the fin surface and improving the conditions of free convection, the external finning in the condensation zone can be made in the form of segments divorced in opposite directions by an angle of not more than 45 (for segments divorced to the TT axis, and (not more than 90 ° for segments divorced on the outside of the CT.

the gap between adjacent segments should not exceed the average thickness of the ribs.

To ensure minimum thermal resistance between CT and SPP, the recommended surface cleanliness in the area of thermal contact should be no worse than Ra 1.25.

The implementation of heat pipes based on a profile equipped with external fins, allows to reduce the dimensions of the device and its material consumption. Heat pipes made on the basis of aluminum profiles with an internal capillary structure in the form of axial grooves of a rectangular, trapezoidal and other shape, provide high heat transfer capacity with minimum dimensions and weight. The inventive design is more simple in the technological and constructive design, since it allows to exclude a number of technological operations such as: the production of an inserted porous structure, the manufacture of ribs with their subsequent placement on the surface of the CT. The use of a homogeneous material (aluminum profile) and such coolants as ammonia and organic liquids eliminates the corrosion processes that inevitably arise when using dissimilar materials. The use of these coolants is primarily determined by their good compatibility with the profile material.

The location of the condensation zone of the heat pipes above the evaporation zone provides a stable mode of swelling of the coolant film on the inner surface of the profile and an additional influx of the coolant into the evaporation zone due to the action of gravitational forces, increasing the transmitted thermal power of the TT.

Figure 1 shows the design of a device with a varying bending angle of the CT in the assembly and having one condensation zone.

In Fig.2 is a section of the device depicted in Fig.1, based on a single-channel type CT.

In Fig.3 is a sectional view of the device depicted in Fig.1, based on two CTs of a single-channel type, connected by welding.

Figure 4 shows the design of the device with parallel pipes and having two condensation zones located symmetrically with respect to the evaporation zone.

Figure 5 shows the design of the device with pipes displaced in the horizontal plane relative to each other by an angle β = 180 / n, where n is the number of elements to be cooled.

Figure 6 shows an embodiment of the external ribbing in the form of segments bent in opposite directions by angles (- no more than 45 (and (- no more than 90 °. The width of the cuts between adjacent segments (b) should be less than the average thickness of the rib (a) .

A device for cooling and temperature control of semiconductor devices contains heat pipes 1 having an evaporation zone 2 and a condensation zone 3, cooled elements 4, which are located between the pipes 1 with thermal contact. Heat pipes are made on the basis of the profile and are equipped with an internal capillary structure 5 in the form of axially spaced grooves, as shown in FIG. 2 and FIG. 3. The heat pipes have an external fin 6, which is formed with the formation of parallel contact surfaces (heat contact zone) 7 located in the evaporation zone 2. Heat pipes outside the evaporation zone are bent so that their condensation zone 3 is located above the heat contact zone 7, as shown figure 1 and figure 4.

The device operates as follows.

When the cooled semiconductor devices 4 are turned on, heat losses from them are transferred through the contact surface 7 to the evaporation zone 2 of the heat pipe 1. The heat carrier evaporating in the capillary structure 5, for example acetone, transfers the vapor to the condensation zone 3, where it condenses to the wall of the condensation zone. From the outside

the surface of the condensation zone and, especially from the surfaces of the fins 6, the heat is dissipated by air due to free convection into the surrounding space. As a result of dissipation of heat losses from semiconductor elements, the permissible temperature of their operation does not exceed the specified values.

To ensure the operational characteristics of the cooled elements, in particular, the thyristor module, two types of grooved TTs were manufactured based on the AC-KRA7,3-P2 (single-channel) profile and TP50-13 (two-channel) profile. As the material of the profiles, aluminum alloy AD31 GOST 4784-97 was used. As a heat carrier for TT, acetone, which was thoroughly purified, was used. The design of a device for cooling and temperature control of a thyristor module based on CTs made of AC-KRA7.3-P2 profile is an assembly of six thyristors and seven (Fig. 4) two-tube CTs, each of which is welded from two single-channel CTs with a curved a welded structure with a rectangular bilateral double-sided contact pad measuring 70x50 mm, which is the heat supply zone emitted by the thyristors (heat contact zone). TT condensation zones symmetrically located relative to the thermal contact zone (evaporation zone) are inclined to the plane of the contact area at an angle of 5 (to ensure a stable mode of coolant sweeping along the inner surface of the profile.

The thyristor module is made of six series-connected thyristors TZ53-80-32 and operates in burst-pulse mode.

The overall dimensions of the device in an assembly with a thyristor module are limited to 500 mm in height and 500 x 150 mm in cross section. The gap between any two adjacent CTs assembled in an assembly is not more than 10 mm. To provide the necessary heat

The contact device was assembled with the application of an axial force of 2000 kg. The contact surfaces of the CTs in contact with the thyristors were machined with a flatness of not more than 0.03 mm and a roughness of not more than 2 μm.

The second version of the device based on two-channel TTs made of a solid TP50-13 profile is structurally similar to the first.

The thermal power generated by the thyristors during their operation is absorbed by the CT and dissipated due to free convection in a production room. In this case, the joint temperature “TT - thyristor” at an ambient temperature of up to 298 K does not exceed 333 K.

Thus, the inventive device provides the possibility of air cooling of semiconductor devices in the conditions of packet-pulse loading and overall limitations. This design has greater compactness and simplicity compared to the prototype due to the use of a serial profile, is more simple in technological design and less material intensive. The use of a homogeneous profile material compatible with the coolant eliminates the appearance of corrosion and increases the resource. The selected combination of the design of the CT and its heat transfer characteristics allows us to optimally solve the problem of organizing the thermal regime of semiconductor devices.

Claims (8)

1. Device for cooling and temperature control of semiconductor devices, made in the form of an assembly of heat pipes with fins having an evaporation zone and a condensation zone, and cooled elements located between the pipes to form a heat contact zone, characterized in that the heat pipes are made on the basis of the profile, equipped with an internal capillary structure in the form of axially located grooves, the outer fins are formed with the formation of parallel contact surfaces in the evaporation zone, and the heat pipe outside the evaporation zone, it is bent so that the condensation zone of the heat pipes is located above the heat contact zone. 2. The device for cooling and thermostating semiconductor devices according to claim 1, characterized in that the evaporation zone is located in the center of the heat pipe profile, and the condensation zone forms two symmetrical parts. 3. The device for cooling and thermostating semiconductor devices according to claim 1 or 2, characterized in that the condensation zone of the heat pipes is located relative to the heat contact zone at an angle α = 5-50 °. 4. A device for cooling and thermostating semiconductor devices according to claim 1 or 2, characterized in that the heat pipes in the assembly are parallel to each other. 5. The device for cooling and thermostating semiconductor devices according to claim 1 or 2, characterized in that the heat pipes in the assembly are offset in the horizontal plane relative to each other by an angle β = 180 / n, where n is the number of elements to be cooled. 6. The device for cooling and thermostating semiconductor devices according to claim 1 or 2, characterized in that the bending angle of the heat pipes in the assembly increases from the lower heat pipe to the upper. 7. The device for cooling and thermostating semiconductor devices according to claim 1 or 2, characterized in that the outer fins in the condensation zone are made in the form of segments, divorced in opposite directions by angles γ - not more than 45 ° and θ - not more than 90 °, the thickness of the cuts between adjacent segments should be less than the average thickness of the ribs. 8. The device for cooling and thermostating semiconductor devices according to claim 1, characterized in that the cleanliness of the contact surfaces should be no worse than Ra 1.25.