Power conversion device

Abstract

A power conversion device according to one embodiment of the present invention comprises: a housing; and an inductor disposed in an inner space of the housing, wherein the inductor includes a core and a coil wound around the core and is disposed such that a surface through which the coil is exposed to the outside faces the air flow direction inside the housing.

Description

power conversion device

[0001] The present invention relates to a power conversion device, and more specifically, to a power conversion device having a high heat dissipation effect of an inductor.

[0002] Rapid chargers for electric vehicles support high-speed charging at hundreds of kilowatts. They consist of power modules with capacities of tens of kilowatts, connected in parallel, and output a large amount of power. When connected to an electric vehicle, the power modules receive AC power from the grid and output DC power to charge the electric vehicle's battery.

[0003] Power conversion within a power module generates significant heat. The resonant inductor in the resonant circuit that makes up the power module is one of the heat-generating components. To ensure product reliability, technology is needed to enhance the heat dissipation of the resonant inductor.

[0004] The technical problem to be solved by the present invention is to provide a power conversion device having a high heat dissipation effect of an inductor.

[0005] In order to solve the above technical problem, a power conversion device according to one embodiment of the present invention includes a housing; and an inductor disposed in an internal space of the housing, wherein the inductor includes a core and a coil wound around the core, and the inductor is disposed such that a surface of the coil exposed to the outside faces the direction of air flow within the housing.

[0006] In addition, a fan is included that is arranged in the inner space of the housing and draws air inwardly of the housing, and the air flow direction can be formed by the fan.

[0007] Additionally, the fan may be disposed on one side of the housing, and the housing may include one or more holes through which air is discharged to the outside on the opposite side of the one side where the fan is disposed.

[0008] Additionally, the central axis of the core of the inductor may be arranged in a direction perpendicular to the air flow direction.

[0009] In addition, the housing may include a substrate disposed in an internal space, the inductor may be mounted on the substrate, and the central axis of the core of the inductor may be disposed in a direction perpendicular to the upper surface of the substrate.

[0010] Additionally, the inductor may include a plurality of inductors, and the plurality of inductors may be arranged in a direction perpendicular to the air flow direction.

[0011] Additionally, the core includes a midfoot, and the midfoot has a midfoot gap formed in the center, and the separation direction of the midfoot gap can be perpendicular to the air flow direction.

[0012] Additionally, the core may not be formed in the above-mentioned mid-gap region.

[0013] Additionally, the power conversion device may include a resonant LLC converter.

[0014] Additionally, the inductor may be a resonant inductor of the resonant LLC converter.

[0015] According to embodiments of the present invention, by arranging the coil surface of the resonant inductor so that it faces the direction of fan flow without using a bobbin, the heat dissipation effect due to fan flow can be increased compared to when a bobbin is used or the coil surface is parallel to the direction of fan flow. In addition, by securing space for air flow between the mid-foot and the coil, heat conduction between the core and the coil can be prevented, and the heat dissipation effect can be improved.

[0016] FIG. 1 illustrates a power conversion device according to one embodiment of the present invention.

[0017] Figure 2 is a block diagram of a power conversion device according to an embodiment of the present invention.

[0018] Figure 3 is a circuit diagram of a power conversion device according to an embodiment of the present invention.

[0019] FIG. 4 and FIG. 5 are drawings for explaining an inductor and a fan of a power conversion device according to an embodiment of the present invention.

[0020] Figures 6 to 8 illustrate an inductor of a power conversion device according to an embodiment of the present invention.

[0021] Figures 9 and 10 illustrate an inductor of a power conversion device according to a comparative example of the present invention.

[0022] Hereinafter, a preferred embodiment of the present invention will be described in detail with reference to the attached drawings.

[0023] However, the technical idea of ​​the present invention is not limited to some of the embodiments described, but can be implemented in various different forms, and within the scope of the technical idea of ​​the present invention, one or more of the components between the embodiments can be selectively combined or substituted for use.

[0024] In addition, terms (including technical and scientific terms) used in the embodiments of the present invention may be interpreted as having a meaning that can be generally understood by a person of ordinary skill in the technical field to which the present invention belongs, unless explicitly and specifically defined and described, and terms that are commonly used, such as terms defined in a dictionary, may be interpreted in consideration of the contextual meaning of the relevant technology.

[0025] Additionally, the terms used in the embodiments of the present invention are intended to describe the embodiments and are not intended to limit the present invention.

[0026] In this specification, the singular may also include the plural unless specifically stated otherwise in the phrase, and when it is described as “A and / or at least one (or more) of B, C”, it may include one or more of all combinations that can be combined with A, B, C.

[0027] Additionally, in describing components of embodiments of the present invention, terms such as first, second, A, B, (a), (b), etc. may be used. These terms are only intended to distinguish the components from other components, and are not intended to limit the nature, order, or sequence of the components.

[0028] And, when a component is described as being 'connected', 'coupled', or 'connected' to another component, it may include not only cases where the component is 'connected', 'coupled', or 'connected' directly to the other component, but also cases where the component is 'connected', 'coupled', or 'connected' by another component between the component and the other component.

[0029] Additionally, when described as being formed or arranged "above" or "below" each component, "above" or "below" includes not only cases where the two components are in direct contact with each other, but also cases where one or more other components are formed or arranged between the two components. Furthermore, when expressed as "above" or "below," the meaning may include not only the upward direction but also the downward direction based on one component.

[0030] Fig. 1 illustrates a power conversion device according to one embodiment of the present invention. The power conversion device (100) according to one embodiment of the present invention is composed of a housing (110) and an inductor (120), and may include a cover (130), a fan (140), a substrate (150), a resonant LLC converter (101), an AC-DC rectifier (102), a primary switching circuit (103), a resonant circuit (104), a transformer (105), and a secondary rectifier circuit (106).

[0031] A power conversion device (100) according to an embodiment of the present invention may be a power conversion device of an electric vehicle charging device. Here, the power conversion device (100) may be a power module of the electric vehicle charging device. The power module may receive AC power from a grid (50 / 60 Hz), convert it into DC power for charging an electric vehicle battery, and output the converted DC power. The power module may include an AC-DC rectifier and an isolated DC-DC converter, and the power conversion device (100) according to an embodiment of the present invention may include an isolated DC-DC converter, and among the isolated DC-DC converters, may include a resonant LLC converter.

[0032] A power conversion device (100) according to an embodiment of the present invention may include a primary-side switching circuit (103), a resonant circuit (104), a transformer (105), a secondary-side rectifier circuit (106), and an AC-DC rectifier (102). As shown in FIG. 2, the power conversion device (100) may include a resonant LLC converter (101) and may further include an AC-DC rectifier (102). AC power input from a grid (210) may be converted into direct current in the AC-DC rectifier (102), and may be output by being converted into power for charging an electric vehicle battery (220) in the resonant LLC converter (101). The resonant LLC converter (101) may include a primary switching circuit (103), a resonant circuit (104), a transformer (105), and a secondary rectifier circuit (106), and may be implemented as a circuit as shown in FIG. 3. The primary switching circuit (103) inputs input power to the primary side of the transformer, and the power input through the primary switching circuit (103) is output to the electric vehicle battery (220) through the transformer (105) and the secondary rectifier circuit (106). When the primary switching circuit (103) operates, zero switching is possible using the resonant frequency implemented in the resonant circuit (104), so that switching loss can be reduced and efficiency can be improved. The resonant circuit (104) uses a resonant capacitor, a resonant inductor (120), and a magnetizing inductance included in a transformer, and is called a resonant LLC converter (101).

[0033] A power conversion device (100) according to an embodiment of the present invention may include a housing (110) and a cover (130) covering the housing (110).

[0034] Components for power conversion are arranged in the internal space of the housing (110), and the components arranged in the internal space of the housing (110) include an inductor (120). Here, the inductor (120) may be a resonant inductor of a resonant circuit (104). In addition, it may be another inductor or coil included in the power conversion device (100).

[0035] The inductor (120) includes a core (123) and a coil (124) wound around the core (123). The core (123) includes a middle group and may include one or more outer groups. The inductor (120) may include various forms of inductors including a coil (124) wound around the core (123).

[0036] The inductor (120) may be arranged so that the surface of the coil (124) exposed to the outside faces the air flow direction (D1) inside the housing (110). In order to efficiently dissipate heat generated in the inductor (120), the inductor (120) does not include a bobbin, so that the coil (124) of the inductor (120) may be exposed to the outside. The surface of the coil (124) of the inductor (120) exposed to the outside faces the air flow direction (D1) inside the housing (110), so that a large area of ​​the coil (124) comes into contact with the flowing air, thereby increasing the heat dissipation efficiency of the inductor (120).

[0037] A fan (140) can be placed in the internal space of the housing (110) to draw in air toward the inside of the housing (110). The air flow direction (D1) can be formed by the fan (140). Heat dissipation to the inside of the housing (110) is performed by a fan air cooling method that performs heat dissipation using the fan (140), and the air flow direction (D1) can be set according to the direction of the fan (140). A bobbin surrounding the coil (124) may not be used so that the surface of the coil (124) of the inductor (120) exposed to the outside can come into contact with the external air having a low temperature drawn in by the fan (140). The inductor (120) can be placed at a position overlapping the air flow direction (D1) formed by the fan (140) to increase the effect of heat dissipation. A location that does not overlap with the air flow direction may result in poor air transfer or air whose temperature has been raised by other components being transferred, which may reduce the heat dissipation effect of the inductor (120). By placing the inductor (120) at a location that overlaps with the air flow direction (D1) formed by the fan (140), the air can directly contact the inductor (120), thereby enhancing the heat dissipation effect of the inductor (120).

[0038] A fan (140) may be placed on one side of the housing (110) and may include one or more holes through which air is discharged to the outside on the opposite side of the side where the fan (140) is placed. The holes may be formed in a mesh shape or as vent holes, etc.

[0039] The inductor includes a plurality of inductors (121, 122), and the plurality of inductors (120) may be arranged in a direction perpendicular to the air flow direction (D1). The plurality of inductors (120) may include two or more inductors, and may be arranged side by side in a direction perpendicular to the air flow direction (D1). When the plurality of inductors (120) are arranged side by side in parallel to the air flow direction (D1), heat is transferred from the inductor that contacts the air first to the hot air, thereby increasing the temperature of the air, and the air with the increased temperature flows to the next inductor, so that the heat dissipation efficiency for the inductors located behind may decrease. Therefore, the plurality of inductors (120) may be arranged side by side in a direction perpendicular to the air flow direction (D1) to increase the heat dissipation effect.

[0040] The fan (140) may include a plurality of fans, and the plurality of fans (140) may be arranged in parallel in a direction perpendicular to the air flow direction (D1). The plurality of fans (140) may be arranged on one side of the housing (110) to draw in external air. The plurality of inductors (121, 122) may be arranged at a position overlapping the air flow direction (D1) formed by the plurality of fans (140) to enhance the heat dissipation effect.

[0041] The central axis of the core (123) of the inductor (120) may be arranged in a direction (D2) perpendicular to the air flow direction (D1). The inductor (120) may be arranged on a substrate (150) that is arranged in the internal space of the housing (110). The inductor (120) is mounted on the substrate (150), and the central axis of the core (123) of the inductor (120) may be arranged in a direction perpendicular to the upper surface of the substrate (150). As shown in FIGS. 6 to 8, the central axis of the core (123) may be arranged to face a direction (D2) perpendicular to the air flow direction (D1) so that the surface of the coil (124) of the inductor (120), not the core (123), that is exposed to the outside may face the air flow direction (D1) inside the housing (110).

[0042] According to a comparative example of the present invention, the inductor may be arranged so that the central axis of the core (23) is parallel to the air flow direction (D1), as shown in FIGS. 9 and 10. In this case, a space is formed between the core (23) and the coil (24) through which air can move, so that the air can flow smoothly. However, the area where the coil (124) meets the air is concentrated only on the coil (24) located in the air inflow direction, and the subsequent coils (24) only allow air to pass sideways, and do not have an area that comes into direct contact with the air, so the efficiency of heat dissipation may be reduced. In contrast, when the central axis of the core (123) is arranged to face the direction (D2) perpendicular to the air flow direction (D1), as shown in FIG. 6, the surface of the coil (124), not the core (123) of the inductor (120), exposed to the outside faces the air flow direction (D1) inside the housing (110), so that the area where the air and the coil (124) come into contact is large, thereby increasing the heat dissipation effect.

[0043] The core (123) of the inductor (120) includes a midfoot, and a midfoot gap (125) may be formed in the center of the midfoot. At this time, the spacing direction of the midfoot gap (125) may be perpendicular to the air flow direction (D1). As shown in FIGS. 7 and 8, by forming the midfoot gap (125), even if the central axis of the core (123) is arranged in a direction (D2) perpendicular to the air flow direction (D1), the air flow may not be obstructed, and the air flow may be made smooth, thereby increasing the heat dissipation effect. In addition, since the core (123) is not formed in the midfoot gap (125) region, the air flow may be made smoother.

[0044] The configuration of forming a mid-foot gap (125) or not forming a core (123) in the mid-foot gap (125) region may not be an essential configuration for ensuring smooth airflow. Even if a mid-foot gap (125) is formed, a core (123) may also be formed in the mid-foot gap (125) region, as shown in FIG. 6. In addition, a configuration in which a coil (124) is wrapped around the core (123) of the inductor (120) can be implemented in various other forms.

[0045] In the case of the inductor (120) according to the embodiment of the present invention and the inductor according to the comparative examples of FIGS. 9 and 10, the maximum temperatures of the core and coil were compared. At this time, as a result of the comparison under the conditions in which the specifications of the fan (140), the specifications of the inductor, the inductor heat generation, and the use of the inductor core and coil were set to the same, it can be confirmed that the inductor (120) according to the embodiment of the present invention and the inductor according to the comparative examples of FIGS. 9 and 10 have core maximum temperatures of 126.8 degrees and 153.7 degrees, respectively, which are about 27 degrees lower for the inductor (120) according to the embodiment of the present invention, and coil maximum temperatures of 130.4 degrees and 151.7 degrees, which are about 21 degrees lower for the inductor (120) according to the embodiment of the present invention. Therefore, it can be confirmed that the heat dissipation effect of the inductor (120) according to the embodiment of the present invention is high.

[0046] Comparative Example of the Invention Core Maximum Temperature (°C) 126.8 153.7 Coil Maximum Temperature (°C) 130.4 151.7

[0047] As described above, by arranging the coil (124) of the inductor (120) so that the surface exposed to the outside faces the direction of flow of the fan (140) without using a bobbin, the heat dissipation effect by fan flow can be enhanced compared to when a bobbin is used or the coil surface is parallel to the direction of flow of the fan. In addition, by securing space for air flow between the midrib and the coil, heat conduction between the core and the coil can be prevented, and the heat dissipation effect can be enhanced.

[0048] Those skilled in the art will appreciate that the present invention can be implemented in modified forms without departing from the essential characteristics of the above-described description. Therefore, the disclosed methods should be considered illustrative rather than restrictive. The scope of the present invention is set forth in the claims, not the foregoing description, and all differences within the scope equivalent thereto should be construed as being encompassed by the present invention.

Claims

1. Housing; and Including an inductor placed in the internal space of the above housing, The above inductor includes a core and a coil wound around the core, The above inductor, A power conversion device in which the surface of the coil exposed to the outside is positioned so as to face the direction of air flow inside the housing.

2. In paragraph 1, A fan is disposed in the inner space of the housing and includes a fan that draws air inward toward the inner side of the housing. The power conversion device in which the above air flow direction is formed by the above fan.

3. In paragraph 1, The above fan is placed on one side of the above housing, A power conversion device wherein the housing includes one or more holes through which air is discharged to the outside on the opposite side of the one side where the fan is placed.

4. In paragraph 1, A power conversion device in which the central axis of the core of the inductor is arranged in a direction perpendicular to the air flow direction.

5. In paragraph 1, Including a substrate placed in the internal space of the above housing, The above inductor is mounted on the above substrate, A power conversion device in which the central axis of the core of the inductor is arranged in a direction perpendicular to the upper surface of the substrate.

6. In paragraph 1, The above inductor comprises a plurality of inductors, A power conversion device in which the plurality of inductors are arranged in a direction perpendicular to the air flow direction.

7. In paragraph 1, The above core includes a midfoot, The above midfoot has a midfoot gap formed in the center, A power conversion device in which the separation direction of the above-mentioned intermediate gap is perpendicular to the air flow direction.

8. In paragraph 7, A power conversion device in which the core is not formed in the above-mentioned intermediate gap region.

9. In paragraph 1, The above power conversion device is a power conversion device including a resonant LLC converter.

10. In paragraph 9, A power conversion device in which the above inductor is a resonant inductor of the above resonant LLC converter.

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