RU2515505C2 - Device for inductance cell cooling - Google Patents

Abstract

FIELD: electricity.

SUBSTANCE: invention is referred to electric engineering, inductance cells used in general and special-purpose electrical equipment, in particular, in alternating voltage converters and electronic ballasts.

EFFECT: technical result lies in reduction of square area of the inductance cell at the mounting surface and increase in total square area of heat dissipation surface for magnet core and windings by creation of mechanical and thermal contact of the heat removing element with at least one lateral side of magnet system side yoke of the inductance cell thus allowing effective heat removal from the magnet system and windings in general.

12 cl, 9 dwg

Description

The cooling device of an inductive element with a ferrite core of a modular type relates to the field of electrical engineering, and in particular to inductive elements used in electrical products of general and special purpose, in particular in voltage converters and electronic ballasts.

A known method of heat dissipation from a planar transformer according to patent US 7920039, priority date 25.09.2008, using at least one radiator, made as a unit with the end part of the side yoke of a magnetic system of a modular type made of ferrite. Disadvantages: heat removal is carried out mainly from one surface of the magnetic system; heat removal from the windings is carried out almost completely through the magnetic system; the heat-dissipating surface of the windings located outside the ferrite core makes a small contribution to heat dissipation, since it has small dimensions in comparison with the entire surface area of the windings.

The inductive component is known, patent US 7508290, priority dated July 21, 2003, in which a ferrite core of a modular type, for example, an RM configuration, is used as a magnetic system; to remove heat from the windings, there is a cooling device comprising at least one composite material with at least one polymeric material and at least one thermally conductive filler. Disadvantages: a large total area occupied by inductive and cooling elements on the mounting surface; heat is removed from one end part of the side yoke, the use of several heat-conducting materials complicates the manufacturing technology and increases the cost of the electrical device.

A known planar voltage converter, patent for utility model No. 116269, priority of 11/30/2011, characterized by: the presence of a fastener 7, which is a heat sink from both parts of the ferrite core; radiator covers 8.9; heat dissipating surfaces 15; printed circuit board 2 and heat-conducting compound 16, filling the free space between the radiator casings 8 and 9. Disadvantages: there is no direct heat removal from the winding; a cooling device occupies an area exceeding the area occupied by the ferrite core; the presence of the casing and its fasteners increases the cost of the assembly process and increases the cost of the whole product.

The optimized mechanical design of the SSM250 power source is known (description on the manufacturer’s website - XP Power company:). In this design, the inductive component is mounted on the board part of the outer surface of one side part of the side yoke, and the end part of the side surface of the yoke of the magnetic system has thermal contact with the side part of the U-shaped heat sink chassis. Disadvantage: heat is removed from only one end part of the side yoke of the armored magnetic system.

Heat-conducting fastening of the winding assembly is known (patent for utility model RU 107394, priority 02/08/2011), in which the polymerized compound performs the functions of fastening, dielectric insulation and heat removal. Disadvantage: heat removal is carried out mainly from the winding.

This technical solution is the closest in design and technological characteristics to the claimed technical solution and therefore is taken as a prototype.

The objectives of the invention are: reducing the area occupied by the inductive element; heat removal from the magnetic system of the inductive element in several directions; heat removal from the end parts of the windings in different directions; reducing the cost of installing an inductive element.

The solution of these problems is achieved by the fact that the cooling device of the inductive element, comprising a magnetic system having two side yokes connecting both ends of the rod; at least one winding; at least one external heat sink; heat conducting element; heat sink from the winding; fastener; characterized in that the magnetic system consists of two joined parts; a fastener connects one external heat sink, the heat sink from the winding and one part of the outer surface of one side of the side yoke, while the longitudinal axis of the core of the magnetic system is offset from the mounting location of one external heat sink and one part of the outer surface of one side of the side yoke along the surface of one external heat sink ; a heat-conducting element fills the free space between the inner surfaces of the side and end parts of the side yokes.

In a preferred embodiment of the device, one external heat sink is a heat-conducting flat sheet.

In a preferred embodiment of the device, the heat-conducting element, the heat sink from the winding and the fastening element are made of thermosetting and thermoplastic polymer resin.

In a preferred embodiment of the device, the magnetic system is made of two symmetrical joined parts.

In a preferred embodiment of the device, the magnetic system is a modular structure made of ferrite and intended for mounting cylindrical coils on a printed circuit board.

In a preferred embodiment, the magnetic system is a ferrite core configuration RM.

In a preferred embodiment, the winding device of the inductive element is made in the form of a set of printed circuit boards.

In another embodiment of the device, one external heat sink is a radiator.

In another embodiment of the device, one external heat sink is made in the form of a U-shaped profile of heat-conducting material.

A variant of the device is possible, in which one external heat sink is made in the form of an open box on one side made of heat-conducting material.

A variant of the device is possible in which heat is removed from the inductive element through several external heat sinks located on at least two external surfaces of the magnetic system

A possible variant of the device in which the magnetic system is a ferrite core configuration PM.

A variant of the device in which the magnetic system is made of two asymmetric docked parts is possible.

Below are the drawings explaining the essence of the claimed technical solution:

figure 1 shows a ferrite core of a modular type, designed for mounting on a board;

figure 2 shows the appearance of the joined parts of the magnetic system; a modular type ferrite core for mounting on a board used in a preferred embodiment of the invention;

figure 3 shows a side view of a preferred embodiment of the invention;

figure 4 shows a top view of a preferred embodiment of the invention;

5 is a cross-sectional view of a preferred embodiment of the invention;

on figa shows a side view for the first embodiment of the installation of the inductive element on the heat sink, made in the form of a U-shaped profile;

on figb shows a top view for the second version of the installation of the inductive element on the heat sink, made in the form of a U-shaped profile;

Fig. 7 is a top view of an embodiment for mounting an inductive element to an external heat sink, made in the form of a duct open on one side;

Fig. 8 is a side view of an inductive installation option.

an element having one and the other external heat sinks;

Fig. 9 is a top view of an installation option of an inductive element having one heat sink and two additional external heat sinks.

The following describes a preferred embodiment of the invention, which is one of the possible options for a cooling device from an inductive element and serves only to explain the essence of the claimed technical solution.

In the solutions known from the prior art, the wire-wound frame is placed inside the magnetic system in the form of a ferrite core 1 and is fixed to the board using soldering (Fig. 1). Structurally, the ferrite core is made of two symmetrical elements, which, when docked, form an armored magnetic system (Fig. 2), having two side parts of the side yoke 2 and 3 (hereinafter: side yoke 2 and side yoke 3), two end parts of the side yokes 4 and 5 (hereinafter: end yoke 4 and end yoke 5) connecting both ends of the rod 6.

In a preferred embodiment of the invention (FIGS. 3-5), a part of the outer surface of the side yoke 2 is placed on the external heat sink 7 by means of the fastening element 8 (hereinafter: part of the side yoke) (FIG. 3). The end parts and lower parts of the surfaces of the set of printed circuit boards 9 placed around the core of the magnetic system 6 through the heat sink from the winding 10 are connected to the mounting device 8 (Fig.3, 5). The heat-conducting element 11 (Fig. 4, 5) having a heat-transfer surface 12 (Fig. 5) is placed in the space between the inner surface of the side yokes 2 and 3 (Fig. 5) and the ends of the set of printed circuit boards 9, as well as between the inner surfaces end yokes 4 and 5 (figure 4) and facing the surfaces of the printed circuit boards 9, and also between the printed circuit boards 9.

3 to 5, the fastener 8, the heat sink from the winding 10 and the heat conductive element 11 are made of one thermoactive, thermoplastic polymer material, for example an epoxy compound, and, at the end of the installation process of the inductive element on one external heat sink element, are a monolithic design having no transitional thermal resistance. Therefore, the boundaries between the fastening element 8, the heat sink from the winding 10 and the heat-conducting element 11 are shown hatched and mean the division of the functions performed. The fastening element 8 connects the inductive element 1, more precisely, part of the side yoke 2 and the heat sink from the winding 10 with an external heat sink 7; a heat sink from the winding 10 connects one part of the winding 9 located outside the region bounded by the magnetic system (Figs. 3, 5) with the fastener 8 and the heat-conducting element 11; the heat-conducting element 11 fills the free space between the side yokes 2 and 3, the end yokes 4 and 5, as well as the gaps between the boards of the winding 9 and forms a heat dissipation surface 12.

Alternatively, as an external heat sink 7, a U-shaped profile of a heat-conducting material having a base and two side parts (FIGS. 6a and 6b) can be used. In the first mounting option (Fig. 6a), the inductive element is fixed to the external heat sink 7 by the fastening element 8 and has another heat-conducting and mechanical contact with the side yoke part 3 through the fastening element 8 and the side part of the external heat sink 7. In this case, the heat sink from the winding 10 is fixed immediately on two external heat sinks 7. In the second mounting option (Fig.6b), an end yoke 4 is attached to the side of the external heat sink 7 through the fastening element 4. The width of the heat sink from the winding 10 is equal to the distance between the external awns end yokes 4 and 5, so heat dissipation from the coil 10 into contact with the side part of the external heat sink 7.

Alternatively, as an external heat sink 7, an open box on one side of a heat-conducting material can be used (Fig. 7). In this case, a part of the side yoke 3 and the end yoke 4 are attached to the sides of the external heat sink 7 through the fastener 8.

Alternatively, another external heat sink 13 may be present in the cooling device of the inductive element, for example, a heat-conducting cover of the device case (Fig. 8). In this case, the external heat sink 13 through the fastening element 8 is connected to a part of the side yoke 3 and the heat sink 14 from another part of the winding 9.

Alternatively, a solution is possible in which additional external heat sinks 15, 16, and 17 are attached to the side yoke 3 and the end yokes 4 and 5 through the fastener 8 (Fig. 9). The inductive element is fixed to the base 7 by a fixing element 8 (not shown in Fig. 9); additional external heat sinks 15 and 17 are attached to both end yokes 4 and 5 through the fastening element 6; An additional external heat sink 16, made, for example, in the form of a radiator, is attached to a part of the side yoke 3 through a fastening element 8. Additional external heat sinks 15-17 can be made in the form of separate elements or represent a U-shaped or closed profile of heat-conducting material. The developed surface can be placed not only as shown in Fig. 9, but also on any of the additional external heat sinks or on its part. It is possible that each additional external heat sink has its own type of developed surface, depending on the conditions of heat dissipation.

In preferred and other embodiments of the device for removing heat from the inductive element, the fastening element is made, for example, of an epoxy compound. This solution allows you to use one fastener from the same material and the same design to fix the inductive element for one, two or three surfaces and to remove heat from all parts of the outer surface of the inductive element and windings.

The electronic device operates as follows.

In the working state of the inductive element, heat is generated from the magnetic system and the winding.

The heat removal from the inductive element in the preferred embodiment of the invention is carried out in different directions as follows.

Part of the heat from the ferrite core 1 is removed through part of the side yoke 2; part of the heat from the winding 9 through the heat-conducting element 11 and the heat sink from the winding 10 is removed through the fastening element 8. This total heat is dissipated on the external heat sink 7 in one direction. The design solution of the heat sink allows using one fastening element 8 to rigidly connect the inductive element 1 and the external heat sink 7, which, as a rule, already has a fastening with the structural parts of the device in which the inductive element is used, or is part of the heat-conducting structure of this device, for example, is the basis of the heat-conducting case of the device.

Part of the heat from the ferrite core 1 is dissipated directly from the side yoke 3 and the end yokes 4 and 5. The heat-conducting element 11, which fills the entire inner space of the ferrite core and is located between the winding boards, fills all the gaps, evenly distributes heat throughout the volume and forms a heat-dissipating surface 12 to remove another part of the heat from the winding. At the same time, parts of the windings protruding beyond the heat-dissipating surface 12 (the upper ones in Figs. 3-5) form a developed surface for heat dissipation in the other direction. This total heat flux is diverted from the inductive element in the other direction.

Variants of the technical solution are intended for the rational use of the spatial distribution of parts and structural units in the volume of an electronic device. For example, in existing technologies for manufacturing voltage converters, general-purpose capacitors with an oxide dielectric are used and the height of the electronic device is determined by the dimensions of the highest capacitor. For mechanical optimization of this design, the device can be used as a magnetic system of an inductive element, for example, a core of a modular type configuration RM or PM. Such an approach to the optimization of the mechanical design will allow the use of such a ferrite core with characteristics that are obviously higher than those calculated for this electrical circuit, which will improve heat removal from the inductive element.

The design options of the external heat sink 7 and / or the use of additional heat sinks (for example, if small height parts are located near the inductive element in the device) make it possible to control the heat fluxes from structurally identical inductive elements designed for use with different voltages and currents.

In the manufacture of a cooling device for an inductive element, commercially available ferrite cores are used; as a set of printed circuit boards can be used known single-sided, double-sided and multi-layer printed circuit boards; options for external heat sinks do not require refinement of well-known cases, metallized boards and radiators. Known polymerizable materials, such as an epoxy compound, are also used, and therefore, the cooling device of the inductive element can be reproduced.

Claims (12)

        1. The cooling device of the inductive element, comprising a magnetic system having two side yokes connecting both ends of the rod; at least one winding, at least one external heat sink, heat-conducting element, heat sink from the winding, fastener, characterized in that the magnetic system consists of two joined parts, the fastener connects one external heat sink, the heat sink from the winding and one part the outer surface of one side part of the side yoke, while the longitudinal axis of the rod of the magnetic system is offset from the attachment point of the external heat sink and one part of the outer surface of one side part of the side yoke along one external surface of the heat sink, a thermally conductive member fills a free space between the inner surfaces of the side and end yokes.        2. The cooling device of the inductive element according to claim 1, characterized in that one external heat sink is a heat-conducting flat sheet.        3. The cooling device of the inductive element according to claim 1, characterized in that one external heat sink is a radiator.       4. The cooling device of the inductive element according to claim 1, characterized in that one external heat sink is made in the form of a U-shaped profile of heat-conducting material.         5. The cooling device of the inductive element according to claim 1, characterized in that one external heat sink is made in the form of an open box on one side made of heat-conducting material.        6. The cooling device of the inductive element according to claim 1, characterized in that the heat-conducting element, the heat sink from the winding and the fastener are made of thermosetting thermoplastic polymer material.        7. The electrical device according to claim 1, characterized in that the magnetic system is made of two symmetrical docked parts.        8. The electrical device according to claim 1, characterized in that the magnetic system is a modular structure made of ferrite and designed to install cylindrical coils on a printed circuit board.        9. The electrical device of claim 8, characterized in that the magnetic system is a ferrite core configuration RM.        10. The electrical device according to claim 8, characterized in that the magnetic system is a ferrite core configuration PM.        11. The electrical device according to claim 1, characterized in that the magnetic system is made of two asymmetric docked parts.        12. The electrical device according to claim 1, characterized in that the winding of the inductive element is made of a set of printed circuit boards.

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