Power conversion device
Patent Information
- Application Number
- JP2023081066
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- Filing Date
- 2023-05-16
- Publication Date
- 2025-09-02
AI Technical Summary
Existing power conversion devices experience uneven cooling performance among heat-generating components due to varying temperatures along the refrigerant flow path, leading to inadequate cooling on the downstream side.
The device employs a cooling section with varying fin structures and increased fin density in the downstream locations to enhance cooling efficiency, ensuring uniform cooling across multiple heat-generating components.
This configuration improves cooling performance by compensating for temperature differences, maintaining optimal operating conditions for all heat-generating components, particularly in high-power applications like electric vehicles.
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Abstract
Description
[Technical field]
[0001] The present invention relates to a power conversion device. [Background technology]
[0002] Power conversion devices such as boost converters and inverters have multiple heat generating components consisting of reactors and semiconductor elements, and various techniques have been proposed for cooling these heat generating components. For example, Patent Document 1 discloses a technique in which a fin group consisting of multiple fins for improving the cooling efficiency of the portion of a cooling pipe closely contacting a semiconductor element is provided corresponding to the semiconductor element, and the center of the fin group is disposed upstream of the center of the semiconductor element corresponding to the fin group in the coolant flow path. [Prior art documents] [Patent documents]
[0003] [Patent Document 1] Patent No. 4985382 Summary of the Invention [Problem to be solved by the invention]
[0004] However, when multiple heat generating components are cooled by the refrigerant flowing through the refrigerant flow path, the degree of cooling differs between the heat generating components on the upstream side of the refrigerant flow path and the heat generating components on the downstream side of the refrigerant flow path, which may cause a temperature difference between the heat generating components. In other words, the refrigerant flowing through the refrigerant flow path becomes hotter the further downstream it is, so there is a concern that the desired cooling performance may not be obtained for the heat generating components on the downstream side.
[0005] The present invention has been made in view of the above-mentioned problems, and has an object to appropriately cool each heat-generating component in a power conversion device having a plurality of heat-generating components. [Means for solving the problem]
[0006] In order to solve the above problems, the power conversion device of the present disclosure is A power conversion device having a plurality of heat-generating components mounted side by side on a base portion which is a component mounting portion, and a cooling portion which is integrally provided on the base portion and cools the plurality of heat-generating components, the cooling unit includes a flow path forming unit that forms a coolant flow path in a direction in which the plurality of heat generating components are arranged, and a fin that extends from an upstream side to a downstream side in the coolant flow path, a portion of the base portion corresponding to each of the heat-generating components is a heat-generating portion, In the cooling section, the fin structures of the upstream and downstream heat generation points among the heat generation points are different, and the downstream heat generation point has a greater number of fins separated from each other in the refrigerant flow direction than the upstream heat generation point.
[0007] In a power conversion device, when multiple heat generating components are cooled in a predetermined order by the refrigerant flowing through the refrigerant flow path of the cooling unit, there is a concern that the cooling performance of the heat generating components downstream of the refrigerant flow path will be reduced compared to the heat generating components upstream of the refrigerant flow path. In light of this, the fin structures of the heat generating parts corresponding to each heat generating component are made different between the upstream heat generating part and the downstream heat generating part, and the downstream heat generating part has a larger number of fins separated from each other in the refrigerant flow direction than the upstream heat generating part. This increases the cooling efficiency of the downstream heat generating part compared to the upstream heat generating part. As a result, each heat generating part can be properly cooled in a power conversion device having multiple heat generating parts.
[0008] In the cooling section, when comparing the most upstream heat generating point and the most downstream heat generating point among the multiple heat generating points lined up along the refrigerant flow path, the most downstream heat generating point may have a larger number of fins in the refrigerant flow direction than the most upstream heat generating point. Also, among the multiple heat generating points lined up along the refrigerant flow path, adjacent heat generating points may include points having the same number of fins in the refrigerant flow direction. [Brief description of the drawings]
[0009] [Figure 1]FIG. 1 is a vertical cross-sectional view showing a schematic configuration of a power conversion device. [Diagram 2] FIG. [Diagram 3] FIG. 4 is a diagram showing a boundary layer formed on a side surface of a fin. [Figure 4] FIG. 13 is a diagram showing a modified example in which a part of the configuration of the cooling unit is changed. [Diagram 5] FIG. 4 is a plan view showing a more specific configuration of each reactor. [Figure 6] FIG. 11 is a diagram showing the configuration of a cooling unit in a second embodiment. [Figure 7] FIG. 13 is a diagram showing the configuration of a cooling unit in a third embodiment. [Figure 8] FIG. 13 is a diagram showing the configuration of a cooling unit in a fourth embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0010] Hereinafter, an embodiment of a power conversion device according to the present invention will be described with reference to the drawings. In this embodiment, a power conversion device used as a boost converter for boosting the voltage of an on-board battery in a power supply system mounted on an electrically-driven vehicle such as a hybrid vehicle or an electric vehicle will be described.
[0011] (First embodiment) As shown in FIG. 1, the power conversion device 10 includes a plate-shaped base portion 11 and a plurality of reactors 12 arranged side by side on the base portion 11. In FIG. 1, three reactors 12 arranged side by side are shown as reactors 12A to 12C. The base portion 11 is made of a metal material such as aluminum. The base portion 11 may be a part of the housing of the power conversion device 10, and serves as a component mounting portion on which the plurality of reactors 12 are mounted. As is well known, the reactor 12 has a core and a coil wound around the core. Each reactor 12 is a single-phase reactor having one coil, or a multi-phase reactor having a plurality of coils. In this embodiment, the reactor 12 corresponds to a "heat generating component."
[0012] In the power conversion device 10, a cooling section 13 for cooling the reactor 12 is provided on the opposite side of the reactor 12 among both sides of the base section 11 in the thickness direction. The cooling section 13 is provided integrally with the base section 11, and has a water-cooled structure (liquid-cooled structure) for cooling the reactor 12 by circulating a refrigerant such as cooling water. The cooling section 13 has a flow path forming section 15 for forming a refrigerant flow path 14, and the refrigerant flow path 14 is formed as a closed space between the base section 11 and the flow path forming section 15 by attaching the flow path forming section 15 to the base section 11. In FIG. 1, the left side of the figure is the upstream side, and the right side is the downstream side, and an inlet section 16 is provided at the most upstream part of the cooling section 13, and an outlet section 17 is provided at the most downstream part. The refrigerant flows in from the inlet section 16, exchanges heat in the refrigerant flow path 14, and then flows out from the outlet section 17.
[0013] The flow path forming portion 15 has a bottom plate portion 15a and a peripheral wall portion 15b, and the base portion 11 and the bottom plate portion 15a are separated by the peripheral wall portion 15b, and the refrigerant flow path 14 is formed therebetween. An inlet portion 16 is provided on one end of the peripheral wall portion 15b in the arrangement direction of the reactors 12, and an outlet portion 17 is provided on the other end. However, instead of this configuration, the peripheral wall portion may be provided on the base portion 11 side. In this case, it is preferable that the inlet portion 16 and the outlet portion 17 are provided on the peripheral wall portion extending from the base portion 11. It is sufficient that the peripheral wall portion surrounding the refrigerant flow path 14 is provided on at least one of the base portion 11 side and the flow path forming portion 15 side.
[0014] Although not shown, an external circulation path for circulating the refrigerant is connected to the refrigerant flow path 14. The external circulation path is provided with, for example, an electric pump and a heat dissipation device such as a radiator, and the refrigerant circulates through the circulation path and the refrigerant flow path 14 of the power conversion device 10 as the pump is driven.
[0015] A plurality of fins 18 extending from the upstream side to the downstream side are provided on the coolant flow path 14 side of both sides in the thickness direction of the base portion 11. The fins 18 are flat plate-shaped. The base portion 11 functions as a heat sink.
[0016] FIG. 2 is a plan view showing the configuration of the cooling unit 13. FIG. 2 corresponds to a cross-sectional view taken along line 2-2 in FIG. 1. In FIG. 2, a plurality of heat generating points X (X1 to X3) caused by each reactor 12 in the base unit 11 are indicated by dashed lines. The heat generating points X are the mounting points of the reactor 12 in the base unit 11, and are the points to be cooled. Here, the heat generating points X corresponding to the three reactors 12A to 12C are referred to as heat generating points X1, X2, and X3, respectively. In terms of the position in the refrigerant flow path 14, the heat generating point X1 is the heat generating point on the most upstream side, the heat generating point X2 is the heat generating point in the middle position, and the heat generating point X3 is the heat generating point on the most downstream side.
[0017] In Fig. 2, a pair of peripheral wall portions 15b are provided at a predetermined interval, and the space therebetween forms a refrigerant flow path 14. The refrigerant flow path 14 is provided so as to overlap with each of the heat generation points X1 to X3. The refrigerant flow path 14 does not turn back along the way and allows the refrigerant to flow in one direction. The fins 18 extend from the upstream side to the downstream side in the refrigerant flow path 14, and are provided in plurality aligned parallel to the width direction of the refrigerant flow path 14.
[0018] The fins 18 are divided at positions Y1 and Y2 between the heat generating points X1 to X3 in the coolant flow direction. Thus, a fin group 21 consisting of a plurality of fins 18 is provided for each of the heat generating points X1 to X3. In this embodiment, the fin group 21 includes first to third fin groups 21A to 21C. The fin groups 21A to 21C are separated from each other in the coolant flow direction. The first fin group 21A is a fin group provided at the heat generating point X1, the second fin group 21B is a fin group provided at the heat generating point X2, and the third fin group 21C is a fin group provided at the heat generating point X3. Each of the fin groups 21A to 21C is composed of a plurality of fins 18 arranged in a row in a direction perpendicular to the coolant flow direction. In FIG. 2, the number of fins in each row arranged in a direction perpendicular to the coolant flow direction is four, but this is an example, and five or more fins 18 may be arranged.
[0019] Among the fin groups 21A-21C, the first and second fin groups 21A, 21B and the third fin group 21C have different fin structures, and the third fin group 21C has a greater number of fins divided in the refrigerant flow direction than the other fin groups 21A, 21B. Specifically, the first and second fin groups 21A, 21B have zero fin divisions (one fin) in the refrigerant flow direction at heat generation points X1, X2, whereas the third fin group 21C has one fin division (two fins) in the refrigerant flow direction at heat generation point X3. That is, in cooling section 13, the number of fins separated from each other in the refrigerant flow direction is greater at heat generation point X3 on the downstream side than at heat generation points X1, X2 on the upstream side.
[0020] In addition, in third fin group 21C (downstream heat generation location X3), the length of fins 18 is shorter than those of the upstream fin groups 21A and 21B. In third fin group 21C, multiple fins 18 (four in the figure) are aligned in the width direction of refrigerant flow path 14 and are provided in two rows in the refrigerant flow direction.
[0021] 2, between the two upstream heat generation locations X1 and X2, it is also possible to provide one continuous fin group 21 rather than dividing the fin group 21 into two. That is, it is also possible to integrate the first and second fin groups 21A and 21B into one.
[0022] In the cooling section 13 shown in FIG. 2, in the third fin group 21C, the number of fins in the refrigerant flow direction is greater than that on the upstream side, and the length of the fins 18 is shorter than that of the upstream fins 18, so that the boundary layer formed on the fin side is smaller, and the decrease in the heat transfer coefficient of the fins 18 is suppressed. That is, when a flat fin 18 is present in the flow of the refrigerant, a boundary layer Z is formed from the tip of the fin 18 along the flow direction as shown in FIG. 3(a), and the boundary layer Z becomes thicker toward the downstream side. The thicker the boundary layer Z, the lower the heat transfer coefficient. In this regard, by dividing the fin 18 in the refrigerant flow direction and shortening the length of the fin 18 as shown in FIG. 3(b), the boundary layer Z is prevented from becoming thick, and the boundary layer Z can be kept thin. As a result, the decrease in the heat transfer coefficient is suppressed in the third fin group 21C, and the cooling performance can be improved.
[0023] In FIG. 2, at the two upstream heat generating points X1 and X2, i.e., at the points corresponding to the rear sides of the two upstream reactors 12A and 12B (opposite sides across the base portion 11), the fin groups 21 are not separated in the refrigerant flow direction, but are separated in the refrigerant flow direction only at the points between the heat generating points X1 and X2. In contrast, at the most downstream heat generating point X3, i.e., at the point corresponding to the rear side of the most downstream reactor 12C, the fin groups 21 are separated in the refrigerant flow direction. As a result, at the heat generating points X1 and X2, the degree of destruction of the boundary layer Z is relatively small, and the heat exchange at each fin group 21 is suppressed, thereby suppressing the rise in the refrigerant temperature. On the other hand, at the heat generating point X3, the boundary layer Z is thinner than at the upstream heat generating points X1 and X2. Therefore, the decrease in cooling capacity due to the rise in the refrigerant temperature at the upstream heat generating points X1 and X2 can be compensated for by the increase in cooling capacity due to the inhibition of the development of the boundary layer thickness.
[0024] Here, among the fin groups 21A-21C, only the third fin group 21C on the most downstream side has its cooling performance improved by dividing the fins 18. In comparison with the two upstream heat generating points X1 and X2 and the most downstream heat generating point X3, the cooling performance is improved only for the most downstream heat generating point X3. In this case, when the refrigerant passes through the upstream heat generating points X1 and X2 in the refrigerant flow path 14, the refrigerant temperature rises due to heat exchange. Even if the temperature difference between the temperature of the most downstream heat generating point X3 and the refrigerant temperature becomes small due to the rise in the refrigerant temperature, the decrease in cooling efficiency can be compensated for by the fin structure different from that on the upstream side. This makes it possible to equalize the cooling rate throughout the cooling section.
[0025] It can also be said that compared to third fin group 21C on the most downstream side, first fin group 21A on the most upstream side has a reduced cooling efficiency.
[0026] As shown in FIG. 2, the fins 18 of each of the fin groups 21A-21C are provided at each of the heat generating points X1-X3 as straight fins in the shape of a straight plate. The fins 18 of the first fin group 21A on the most upstream side are provided to include a straight excess portion extending upstream of the heat generating point X1, and the fins 18 of the third fin group 21C on the most downstream side are provided to include a straight excess portion extending downstream of the heat generating point X3. This allows the flow of the refrigerant to be adjusted near the inlet and outlet of the refrigerant flow path 14, improving the flow of the refrigerant and ensuring the cooling efficiency of the entire flow path. The fin groups 21A and 21C on the most upstream and most downstream sides have excess portions upstream and downstream of the heat generating points X1 and X3, and it is preferable that the excess portions are longer upstream of the heat generating point X1 and downstream of the heat generating point X3.
[0027] FIG. 4 shows a modification in which the cooling section 13 shown in FIG. 2 is partially modified.
[0028] In Fig. 4(a), the fin structures of the first and second fin groups 21A and 21B and the third fin group 21C are different, similar to Fig. 2. However, the fin structure of the third fin group 21C is changed from the configuration in Fig. 2, and the number of fin divisions in the refrigerant flow direction is now two (the number of fins is three).
[0029] In Fig. 4(b), the first fin group 21A has a different fin structure from the second and third fin groups 21B and 21C. Specifically, the first fin group 21A has a fin division number in the refrigerant flow direction at the heat generation point X1 of zero (the number of fins is one), whereas the second and third fin groups 21B and 21C have a fin division number in the refrigerant flow direction at the heat generation points X2 and X3 of one (the number of fins is two). In this configuration, as in the configuration of Fig. 2, the number of fins separated in the refrigerant flow direction is greater at the downstream heat generation points (heat generation points X2 and X3) in the cooling section 13 than at the upstream heat generation point (heat generation point X1). Also, the second and third fin groups 21B and 21C have shorter fins 18 than the upstream first fin group 21A.
[0030] In Fig. 4(c), the fin structures of the fin groups 21A to 21C are different from one another. Specifically, in the first fin group 21A, the number of fins divided in the coolant flow direction at heat generation location X1 is zero (the number of fins is one), in the second fin group 21B, the number of fins divided in the coolant flow direction at heat generation location X2 is one (the number of fins is two), and in the third fin group 21C, the number of fins divided in the coolant flow direction at heat generation location X3 is two (the number of fins is three). In this configuration, as in the configuration of Fig. 2, in cooling section 13, the number of fins separated in the coolant flow direction is greater at the heat generation location on the downstream side than at the heat generation location on the upstream side.
[0031] According to the present embodiment described above in detail, the following excellent effects can be obtained.
[0032] In the power conversion device 10, when the multiple reactors 12 are cooled in a predetermined order by the refrigerant flowing through the refrigerant flow path 14 of the cooling unit 13, there is a concern that the cooling performance of the reactor 12 downstream of the refrigerant flow path 14 will be reduced compared to the reactor 12 upstream of the refrigerant flow path 14. In consideration of this point, the fin structure is made different between the upstream heat generating location and the downstream heat generating location among the heat generating locations X1 to X3 corresponding to each reactor 12, and the downstream heat generating location has a larger number of fins separated from each other in the refrigerant flow direction than the upstream heat generating location. This increases the cooling efficiency of the downstream heat generating location compared to the upstream heat generating location. As a result, each reactor 12 can be properly cooled in the power conversion device 10 having multiple reactors 12.
[0033] In the third fin group 21C (heat generating point X3) on the most downstream side of the fin groups 21A to 21C, the number of fins in the refrigerant flow direction is made greater than that on the upstream side, and the length of the fins 18 is made shorter than that of the upstream fin groups (heat generating points X1, X2). In this case, in the third fin group 21 on the most downstream side, the development of a boundary layer can be suppressed, and cooling efficiency can be ensured.
[0034] 4(c), the number of fins in the refrigerant flow direction increases in the order of first fin group 21A, second fin group 21B, and third fin group 21C (i.e., heat generation point X1 on the most upstream side, heat generation point X2 at the intermediate position, and heat generation point X3 on the most downstream side). In this case, by lowering the cooling efficiency of heat generation point X1 on the most upstream side and increasing the cooling efficiency of heat generation point X3 on the most downstream side relative to heat generation point X2 at the intermediate position, it is possible to realize a configuration suitable for equalizing the degree of cooling for each of reactors 12A to 12C of power conversion device 10.
[0035] The multiple reactors 12 (12A to 12C) are arranged in sequence from the upstream side to the downstream side of the coolant flow path 14 on the surface opposite to the surface on which the cooling unit 13 is provided in the base unit 11 of the power conversion device 10. In such a power conversion device 10, it can be said that it is particularly practically significant in recent years to be able to uniformly cool the multiple reactors 12 using the same coolant flow path 14. That is, in electric vehicles, the driving force required for the electric motor tends to be large, and the amount of heat generated in the reactor 12 increases with an increase in power (current), while there is a high demand for light weight and miniaturization, so it tends to be difficult to increase the outer shape and layout area of the reactor 12. For this reason, the amount of heat to be cooled per layout area of the reactor 12 is larger than before. Furthermore, among the heat-generating components that constitute the power conversion device 10, the reactor 12 tends to have a larger amount of heat and a larger layout area than semiconductor elements such as inverters. Furthermore, reactors are often arranged side by side. Therefore, the area where the multiple reactors 12 are arranged tends to become hot, which leads to heat being easily trapped.
[0036] The technology of this embodiment can solve the problem of ensuring a temperature environment in which the reactor 12 used in the power conversion device 10 functions properly by adjusting the increase in refrigerant temperature and the thickness of the boundary layer so as to compensate for the decrease in cooling capacity due to the increase in refrigerant temperature with an increase in cooling capacity due to inhibition of the development of the boundary layer thickness.
[0037] A more specific configuration of each reactor 12 shown in Figures 1 and 2 is shown in Figure 5. In Figure 5, each reactor 12 has a substantially ring-shaped core 31 and a pair of coils 32 wound around the core 31, and the pair of coils 32 are arranged spaced apart from each other in the direction in which the reactors 12 are lined up (the left-right direction in the figure). A coil gap is formed between the pair of coils 32. The heat generating point X is generally the area where the reactor 12 is projected in a plan view (the area including the projected portion).
[0038] In this case, the heat generation amount is large at the portion of each heat generation point X corresponding to each coil 32. Therefore, by providing a portion where the fin 18 is separated at a position (gap between the coils) between the pair of coils 32 as shown in Fig. 2 or Fig. 4, the development of the boundary layer in the coolant flow path 14 at the portion corresponding to the coil 32, which is the heat source, can be destroyed, and the cooling efficiency can be improved. Note that, although there are portions of the heat generation point X (inside the dashed frame) where the coil 32 is not present, the heat generation point X in the base part 11 becomes a place where heat is collected by heat transfer in the base part 11, and becomes high temperature. Also, depending on the arrangement direction of the pair of coils 32 of the reactor 12, there are cases where the entire heat generation point X (within the dashed frame) becomes a heat generation point.
[0039] Hereinafter, another embodiment in which the first embodiment is partially modified will be described.
[0040] Second embodiment In this embodiment, the cooling section 13 of the power conversion device 10 has a configuration shown in Fig. 6. In this case, the number of fins in the refrigerant flow direction is greater at the heat generating portion on the downstream side than at the upstream side, and in each row of fins 18 in the refrigerant flow direction, the rear row of fins 18 is arranged between the front row of fins 18 in the refrigerant flow direction. The configuration of Fig. 6 will be specifically described.
[0041] 6(a) and 6(b), the fin structures are different between the first and second fin groups 21A and 21B at the upstream heat generation points X1 and X2 and the third fin group 21C at the downstream heat generation point X3, as in the case of Fig. 2. In particular, in the third fin group 21C, the number of fins divided in the refrigerant flow direction is greater than in the other groups, so that the length of the fins 18 is short, and the fins 18 are arranged alternately in each row in the refrigerant flow direction.
[0042] In FIG. 6(a), in the third fin group 21C, each fin 18 in the first row (fin row on the most upstream side) is arranged on the extension line of each fin 18 in the second fin group 21B, the fins 18 in the second row are arranged between each fin 18 in the first row, and the fins 18 in the third row are arranged between each fin 18 in the second row. The fins 18 in the first and third rows are arranged on the extension line of each fin 18 in the second fin group 21B, but the fins 18 in the third row may be off the extension line of each fin 18 in the second fin group 21B. The fins 18 in the fourth row are provided as straight fins downstream of the heat generation point X3. In FIG. 6(b), the arrangement pattern of the first to third rows is different, but each row is alternately arranged as in FIG. 6(b).
[0043] 6(c), the three fin groups 21A-21C have different fin structures and have different numbers of fin divisions (number of fins) in the coolant flow direction. In this case, the more downstream the fin group, the greater the number of fin divisions (number of fins). In the third fin group 21C, the fins 18 are arranged alternately in each row in the coolant flow direction.
[0044] According to the configuration of the present embodiment, when the coolant flows into third fin group 21C in coolant flow path 14, the coolant hits fins 18 and tends to cause turbulence. This can improve the cooling efficiency in third fin group 21C.
[0045] 6(c), the cooling efficiency of first fin group 21A on the most upstream side can be made lower and the cooling efficiency of third fin group 21C on the most downstream side can be made higher, relative to second fin group 21B in the middle position. This makes it possible to realize a configuration suitable for equalizing the degree of cooling for each of reactors 12A to 12C of power conversion device 10.
[0046] Third embodiment In this embodiment, the cooling section 13 of the power conversion device 10 has a configuration shown in Fig. 7. In this case, the fins 18 at the downstream heat generating portion are provided in a direction intersecting with the fins 18 provided at the upstream heat generating portion. The configuration of Fig. 7 will be specifically described.
[0047] 7(a) and (b), similarly to FIG. 2, the fin structures of the first and second fin groups 21A and 21B at the upstream heat generating points X1 and X2 are different from those of the third fin group 21C at the downstream heat generating point X3. In particular, in this embodiment, the fins 18 in the third fin group 21C are provided in a direction intersecting with the fins 18 of the first and second fin groups 21A and 21B. In other words, the fins 18 of the third fin group 21C are provided at an angle with respect to the fins 18 of the first and second fin groups 21A and 21B. In this case, the fins 18 of the third fin group 21C are provided so as to block the refrigerant passing through the first and second fin groups 21A and 21B on the upstream side, and the cooling efficiency at the heat generating point X3 is improved.
[0048] In the third fin group 21C, the orientation of the fins 18 is different between the first row (front row) and the second row (rear row). Therefore, in the third fin group 21C, the direction of the coolant flow is switched at multiple locations, improving the cooling efficiency. In the third fin group 21C, the orientation of the fins 18 in the last row (fins 18 downstream of the heat generation location X3) is parallel to the peripheral wall portion 15b of the flow path formation section 15 (i.e., the arrangement direction of the heat generation locations X1 to X3), similar to the first and second fin groups 21A and 21B.
[0049] According to the configuration of the present embodiment, the coolant flowing through the coolant flow paths 14 can easily strike the plate surfaces of the fins 18, thereby improving the cooling efficiency in the third fin group 21C.
[0050] (Fourth embodiment) In this embodiment, the cooling section 13 of the power conversion device 10 has a configuration shown in Fig. 8. In this case, long plate-like fins 18 extending from the upstream side to the downstream side in the refrigerant flow path are provided at the upstream heat generating portion, whereas pin-shaped fins are provided aligned in the refrigerant flow direction at the downstream heat generating portion.
[0051] In FIG. 8(a), the third fin group 21C includes fins 18A having a pin shape and flat plate fins 18B having a flat plate shape. The cross section of the pin fins 18A is a perfect circle or an ellipse. When the cross section of the pin fins 18A is an ellipse, the pin fins 18A are preferably arranged so that the major axis of the pin fins 18A is oriented in the direction of refrigerant flow. The diameter of the pin fins 18A (or the minor axis in the case of an ellipse) is preferably larger than the thickness of the flat plate fins 18. The cross section of the pin fins 18A may be other than a circle, and may be a semicircle with an arc on the upstream side, or a polygon with three or more sides.
[0052] The pin fins 18A are provided upstream of the heat generation location X3, and the flat fins 18B are provided downstream of the pin fins 18A. The pin fins 18A are arranged in a plurality of rows in the refrigerant flow direction. At the heat generation location X3, the pin fins 18A are arranged in staggered positions in each row in the refrigerant flow direction. By using the pin fins 18A as the fins 18, the number of fins separated from each other in the refrigerant flow direction can be increased, and the number of fins at the downstream heat generation location X3 can be made greater than the number of fins at the upstream heat generation locations X1 and X2. When comparing the total surface area of the fins 18 at the heat generation locations X1 to X3, it is preferable that the total surface area of the fins 18 at the heat generation location X3 is the largest.
[0053] 8(b), similarly to FIG. 8(a), pin fins 18A and flat fins 18B are provided in third fin group 21C, and in second fin group 21B, fins 18 are divided into two in the refrigerant flow direction.
[0054] According to the configuration of this embodiment, by increasing the number of fins in the coolant flow direction at downstream heat generation point X3 compared to upstream heat generation points X1 and X2, it is possible to improve the cooling efficiency in third fin group 21C.
[0055] (Other embodiments) The above embodiment may be modified, for example, as follows.
[0056] In each of the above embodiments, the power converter 10 is assumed to have three heat generating points on the base 11. However, this may be changed to have two heat generating points or four or more heat generating points. For example, in a configuration having four heat generating points, at least the heat generating point on the most downstream side (fourth heat generating point) may have a different fin structure from the heat generating point on the upstream side, and may have a larger number of fins in the refrigerant flow direction. In this case, in comparison between the heat generating point on the most upstream side and the heat generating point on the most downstream side, the heat generating point on the most downstream side may have a larger number of fins in the refrigerant flow direction than the heat generating point on the most upstream side, and adjacent heat generating points may include the same number of fins in the refrigerant flow direction. In a configuration having n heat generating points along the refrigerant flow direction, the i+1th heat generating point may have the same or a larger number of fins in the refrigerant flow direction than the i-th heat generating point from the most upstream side (1=1 to n-1).
[0057] For example, in a configuration having four heat generating locations, it is preferable that the fin groups 21 are not divided in the refrigerant flow direction at one upstream heat generating location including the most upstream heat generating location, two upstream heat generating locations, or three upstream heat generating locations, and that the fin groups 21 are divided in the refrigerant flow direction at the remaining heat generating locations including the most downstream heat generating location. This makes it possible to suppress the rise in refrigerant temperature at the upstream heat generating location, and to compensate for the decrease in cooling capacity at the downstream heat generating location due to the temperature rise at the upstream side by increasing the cooling capacity by inhibiting the development of the boundary layer.
[0058] The cooling section 13 of the power conversion device 10 may be configured so that a corner portion is provided midway through the refrigerant flow path 14, or a turn (U-turn portion) is provided midway through the refrigerant flow path 14. Even in such a configuration, the fin structure may be made different between the upstream heat generating portion and the downstream heat generating portion, and the downstream heat generating portion may have a larger number of fins in the refrigerant flow direction than the upstream heat generating portion.
[0059] The power conversion device may be an inverter having a plurality of switching devices. In this case, the semiconductor switching elements (switching devices) provided in the inverter are heat-generating components, and the heat-generating components are the targets to be cooled.
[0060] The power conversion device of the present invention may be used in a power supply system for a vehicle, or may be used in a power supply system for other moving objects such as aircraft or ships, or may be used in a stationary power supply system.
[0061] The technical ideas extracted from the above-described embodiments will be described below. [Configuration 1] A power conversion device (10) having a plurality of heat-generating components (12) mounted side by side on a base portion (11) which is a component mounting portion, and a cooling portion (13) which is integrally provided on the base portion and cools the plurality of heat-generating components, the cooling section includes a flow path forming section (15) that forms a refrigerant flow path (14) in a direction in which the plurality of heat generating components are arranged, and fins (18) that extend from an upstream side to a downstream side in the refrigerant flow path, a portion of the base portion corresponding to each of the heat-generating components is a heat-generating portion, A power conversion device in which the fin structures of the upstream heat generation points and the downstream heat generation points among the heat generation points in the cooling section are different, and the downstream heat generation points have a greater number of fins separated from each other in the refrigerant flow direction than the upstream heat generation points. [Configuration 2] The power conversion device according to configuration 1, wherein the number of fins in the coolant flow direction is greater in the heat generating portion on the downstream side than in the upstream side, and the length of the fins in the coolant flow direction is shorter than the length of the fins on the upstream side. [Configuration 3] In the cooling section, a plurality of the fins are arranged in a width direction of the refrigerant flow path at each of the heat generating locations, A power conversion device as described in configuration 1 or 2, wherein the number of fins in the refrigerant flow direction is greater at the heat generation location on the downstream side than at the upstream side, and in each row of fins in the refrigerant flow direction, the fins in a rear row are arranged between the fins in a front row in the refrigerant flow direction. [Configuration 4] The power conversion device according to configuration 1 or 2, wherein the fins at the downstream heat generating location are provided in a direction intersecting with the fins provided at the upstream heat generating location. [Configuration 5] A power conversion device according to any one of configurations 1 to 3, wherein, at the upstream heat generating location, the fins are long plate-shaped and extend from the upstream side to the downstream side in the refrigerant flow path, whereas, at the downstream heat generating location, the fins are pin-shaped and arranged in the refrigerant flow direction. [Configuration 6] At least three of the heat generating components are mounted in a row on the base portion, A power conversion device according to any one of configurations 1 to 5, wherein in the cooling section, the number of fins in the refrigerant flow direction increases in the order of the most upstream side, the intermediate position, and the most downstream side among a heat generation point (X1) on the most upstream side, a heat generation point (X2) at an intermediate position between the most upstream side and the most downstream side, and a heat generation point (X3) on the most downstream side. [Configuration 7] The heat generating component includes a plurality of reactors (12A to 12C), The power conversion device according to any one of configurations 1 to 6, wherein the plurality of reactors are arranged in sequence from the upstream side to the downstream side of the refrigerant flow path on a surface of the base portion opposite to a surface on which the cooling portion is provided. [Explanation of symbols]
[0062] 10... power conversion device, 11... base portion, 12... reactor, 13... cooling portion, 14... refrigerant flow path, 15... flow path forming portion, 18... fins, X1 to X3... heat generation points.
Claims
1. A power conversion device (10) having a plurality of heat-generating components (12) mounted side by side on a base (11) that is a component mounting portion, and a cooling portion (13) that is integrally provided on the base and cools the plurality of heat-generating components, The cooling unit includes a flow path forming unit (15) that forms a refrigerant flow path (14) in a direction in which the plurality of heat-generating components are arranged, and elongated fins (18) that extend from an upstream side to a downstream side in the refrigerant flow path, The fins are provided in a plurality of rows in the width direction of the refrigerant flow path, a portion of the base portion corresponding to each of the heat-generating components is a heat-generating portion, In the cooling section, the upstream heat generation location and the downstream heat generation location among the heat generation locations have different fin structures, At the upstream heat generating portion, the fins of each row are provided without being separated at a midpoint of the heat generating portion in the refrigerant flow direction, whereas In the heat generation area on the downstream side, the fins of each row are separated at a position midway through the heat generation area in the refrigerant flow direction, so that the number of fins in the refrigerant flow direction is greater than that of the heat generation area on the upstream side, and the length of the fins in the refrigerant flow direction is shorter than that of the fins at the heat generation area on the upstream side.
2. The power conversion device according to claim 1 , wherein the fins at the downstream heat generating location are provided in a direction that crosses the fins provided at the upstream heat generating location.
3. At least three of the heat-generating components are mounted side by side on the base portion, 2. The power conversion device of claim 1, wherein the number of fins in the refrigerant flow direction increases in the order of the most upstream heat generating point (X1), the heat generating point (X2) at an intermediate position between the most upstream and most downstream sides, and the heat generating point (X3) at the most downstream side in the cooling section.
4. The heat generating component includes a plurality of reactors (12A to 12C), The power conversion device according to any one of claims 1 to 3, wherein the plurality of reactors are arranged in sequence from the upstream side to the downstream side of the refrigerant flow path on a surface of the base portion opposite to a surface on which the cooling portion is provided.