Cooling device and power conversion device

Abstract

To prevent a decrease in cooling performance downstream of a refrigerant.SOLUTION: A cooling device 20 includes a cooling surface extending along the X2 and Y2 directions that intersect with each other, and an internal space S through which a refrigerant flows to cool the cooling surface. The internal space S includes a first space S1, a second space S2 located in the X2 direction of the first space S1, a third space S3 located in the Y2 direction of the first space S1, a fourth space S4 located in the Y2 direction of the second space S2, a first communication passage P1 that connects the first space S1 with the fourth space S4, and a second communication passage that connects the second space S2 with the third space S3.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present disclosure relates to a technique for cooling a heat-generating body. [Background technology]

[0002] Techniques for cooling heat-generating elements such as semiconductor modules have been proposed in the past. For example, Patent Document 1 discloses a heat sink that includes a pair of first inner fins arranged in parallel in the width direction with a first bypass passage between them, a second inner fin installed downstream of the first bypass passage with a space therebetween, and a flat funnel-shaped partition installed in the space. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2016-62919 Summary of the Invention [Problem to be solved by the invention]

[0004] In a configuration in which a heat generating element such as a semiconductor module is installed along the direction of the coolant, the temperature of the coolant gradually increases as it flows along the heat generating element, and as a result, there is a possibility that sufficient cooling performance cannot be maintained downstream of the coolant. In consideration of the above circumstances, one aspect of the present disclosure aims to suppress a decrease in cooling performance downstream of the coolant. [Means for solving the problem]

[0005] In order to solve the above problems, a cooling device according to one embodiment of the present disclosure is a cooling device including a cooling surface extending along a first direction and a second direction that intersect with each other, and an internal space through which a refrigerant that cools the cooling surface flows, wherein the internal space includes a first space, a second space located in the first direction of the first space, a third space located in the second direction of the first space, a fourth space located in the second direction of the second space, a first communication passage connecting the first space and the fourth space, and a second communication passage connecting the second space and the third space.

[0006] A power conversion device according to one embodiment of the present disclosure comprises a power conversion unit including a first circuit unit and a second circuit unit having different heat generation amounts, a cooling device including a cooling surface along a first direction and a second direction that intersect each other, and an internal space through which a refrigerant that cools the cooling surface flows, wherein the cooling surface includes a first region that extends in the second direction and in which the first circuit unit is installed, and a second region that extends in the second direction in the first direction of the first region and in which the second circuit unit is installed, and the internal space includes a first space corresponding to the first region, a second space that corresponds to the second region and is located in the first direction of the first space, a third space that corresponds to the first region and is located in the second direction of the first space, a fourth space that corresponds to the second region and is located in the second direction of the second space, a first communication passage that connects the first space with the fourth space, and a second communication passage that connects the second space with the third space. [Brief explanation of the drawings]

[0007] [Figure 1] 1 is a perspective view of a power conversion device according to a first embodiment. [Figure 2] FIG. 2 is a plan view of the power conversion device. [Figure 3] FIG. 2 is a side view of the power conversion device. [Figure 4] FIG. 4 is a plan view taken along line IV-IV in FIG. [Figure 5] FIG. 4 is a plan view taken along line VV in FIG. [Figure 6]FIG. 6 is a cross-sectional view taken along line VI-VI in FIGS. 4 and 5. [Figure 7] FIG. 7 is a cross-sectional view taken along line VII-VII in FIGS. 4 and 5. [Figure 8] FIG. 4 is an enlarged perspective view of the vicinity of a first flow path wall. [Figure 9] FIG. 2 is a circuit diagram of a power conversion unit. [Figure 10] FIG. 2 is a plan view illustrating an example of the positional relationship between a cooling device and a power conversion unit. [Figure 11] FIG. 4 is an explanatory diagram of the effect of the first embodiment. [Figure 12] 10 is a plan view illustrating an example of the positional relationship between a cooling device and a power conversion unit in the second embodiment. FIG. [Figure 13] FIG. 10 is a circuit diagram of a power conversion unit in a third embodiment. [Figure 14] 10 is a plan view illustrating an example of the positional relationship between a cooling device and a power conversion unit in a third embodiment. FIG. [Figure 15] FIG. 10 is a circuit diagram of a power conversion unit in a fourth embodiment. [Figure 16] 10 is a plan view illustrating an example of the positional relationship between a cooling device and a power conversion unit in a fourth embodiment. FIG. [Figure 17] FIG. 10 is an explanatory diagram of an internal space in a modified example. [Figure 18] FIG. 10 is an explanatory diagram of an internal space in a modified example. [Figure 19] FIG. 10 is a plan view of an internal space in a modified example. DETAILED DESCRIPTION OF THE INVENTION

[0008] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] The following description of an embodiment of the present disclosure will be given with reference to the accompanying drawings. Note that the embodiment described below is an exemplary embodiment that may be envisioned when implementing the present disclosure. Therefore, the scope of the present disclosure is not limited to the embodiment exemplified below.

[0009] A: First embodiment Fig. 1 is a perspective view of a power converter 100 according to the first embodiment, Fig. 2 is a plan view of the power converter 100, and Fig. 3 is a side view of the power converter 100.

[0010] As illustrated in Figures 1 to 3, in the following description, three mutually orthogonal axes (X-axis, Y-axis, and Z-axis) are assumed for convenience. A direction along the X-axis is referred to as the "X1 direction," and the direction opposite the X1 direction is referred to as the "X2 direction." Furthermore, a direction along the Y-axis is referred to as the "Y1 direction," and the direction opposite the Y1 direction is referred to as the "Y2 direction." Similarly, a direction along the Z-axis is referred to as the "Z1 direction," and the direction opposite the Z1 direction is referred to as the "Z2 direction." Note that the X2 direction is an example of a "first direction," and the Y2 direction is an example of a "second direction." Furthermore, in the following description, observing an object from a line of sight along the Z-axis is referred to as "planar view."

[0011] As illustrated in FIGS. 1 to 3 , the power conversion device 100 includes a power conversion unit 10 and a cooling device 20. The power conversion unit 10 is a semiconductor device that converts power supplied from an external device (not shown) such as a power supply or a power system. The power conversion unit 10 includes a first circuit unit 11 and a second circuit unit 12. The first circuit unit 11 is a part of the power conversion unit 10, and the second circuit unit 12 is another part of the power conversion unit 10.

[0012] The first circuit section 11 and the second circuit section 12 generate heat during operation of the power conversion section 10. The amount of heat generated by the first circuit section 11 is different from the amount of heat generated by the second circuit section 12. In the following description, it is assumed that the amount of heat generated by the first circuit section 11 exceeds the amount of heat generated by the second circuit section 12.

[0013] The cooling device 20 is a cooler that cools the power conversion unit 10 with a liquid refrigerant. Any type of refrigerant may be used, but examples include aqueous refrigerants such as water, alcohol refrigerants such as methanol, ketone refrigerants such as acetone, and glycol refrigerants such as ethylene glycol. Note that various surfactants and the like may be added to the refrigerant.

[0014] The cooling device 20 includes a housing 30, a supply pipe 21, and a discharge pipe 22. The housing 30 is a hollow structure that is elongated in the Y-axis direction. Specifically, the housing 30 includes a first substrate 31, a second substrate 32, and an outer wall portion 34. The first substrate 31 and the second substrate 32 are rectangular plate-like members that extend along the X-axis and Y-axis. The first substrate 31 is installed in the Z2 direction of the second substrate 32. Specifically, the first substrate 31 and the second substrate 32 face each other with a fixed gap between them. The outer wall portion 34 is a rectangular frame-like member that connects the periphery of the first substrate 31 and the periphery of the second substrate 32. As can be understood from the above description, a flat space (hereinafter referred to as "internal space S") that extends along the X-axis and Y-axis is formed inside the cooling device 20. The internal space S is a flow path through which a refrigerant flows.

[0015] A supply pipe 21 and a discharge pipe 22 are installed on the second substrate 32. Specifically, the supply pipe 21 and the discharge pipe 22 protrude in the Z1 direction from the surface of the second substrate 32 facing in the Z1 direction. The supply pipe 21 is a pipe line for supplying the refrigerant to the internal space S. The discharge pipe 22 is a pipe line for discharging the refrigerant that has passed through the internal space S. That is, generally, as shown by the arrows in FIG. 3 , the refrigerant supplied from the supply pipe 21 moves in the Y2 direction within the internal space S and is discharged from the discharge pipe 22. The supply pipe 21 and the discharge pipe 22 may be installed at any position. For example, the supply pipe 21 or the discharge pipe 22 may be installed on the first substrate 31 or the outer wall portion 34.

[0016] The surface of the first substrate 31 in the Z2 direction is a cooling surface C for cooling the power conversion unit 10. The cooling surface C is a flat surface along the X-axis and Y-axis. The power conversion unit 10 is placed on the cooling surface C. Heat propagated from the power conversion unit 10 to the cooling surface C propagates through the first substrate 31 and is dissipated into the refrigerant in the internal space S. The power conversion unit 10 is cooled by the above heat exchange. As described above, the refrigerant that cools the cooling surface C circulates in the internal space S.

[0017] As illustrated in FIGS. 1 and 2, the cooling surface C includes a first region C1 and a second region C2. The first region C1 and the second region C2 are rectangular regions that are elongated in the Y-axis direction. The second region C2 is located in the X2 direction of the first region C1. That is, the first region C1 and the second region C2 are arranged side by side in the X-axis direction. The first circuit section 11 of the power conversion unit 10 is installed in the first region C1. On the other hand, the second circuit section 12 of the power conversion unit 10 is installed in the second region C2.

[0018] 4 and 5 are plan views of the internal space S. Specifically, Fig. 4 is a plan view taken along line IV-IV in Fig. 3, and Fig. 5 is a plan view taken along line VV in Fig. 3.

[0019] 4 and 5, the outer wall portion 34 is a rectangular frame-shaped structure in which a first side wall 341, a second side wall 342, a third side wall 343, and a fourth side wall 344 are interconnected. The first side wall 341 and the second side wall 342 are rectangular plate-shaped members that are elongated in the Y-axis direction. The second side wall 342 is located in the X2 direction of the first side wall 341. The first side wall 341 and the second side wall 342 face each other with a gap in the X-axis direction.

[0020] The third side wall 343 and the fourth side wall 344 are rectangular plate-like members that are elongated in the X-axis direction. The fourth side wall 344 is located in the Y2 direction of the third side wall 343. The third side wall 343 and the fourth side wall 344 face each other with a gap in between in the Y-axis direction.

[0021] A first flow path wall 351, a second flow path wall 352, a partition plate 36, a first partition wall 371, and a second partition wall 372 are further installed in the internal space S of the cooling device 20. The first flow path wall 351, the second flow path wall 352, the first partition wall 371, and the second partition wall 372 are plate-like members that span the first substrate 31 and the second substrate 32. The housing 30 having the above shape is manufactured by, for example, pressing and welding a metal plate.

[0022] The first flow path wall 351 and the second flow path wall 352 are plate-like members that are elongated in the X-axis direction. Specifically, the first flow path wall 351 and the second flow path wall 352 are located at the center of the internal space S in the Y-axis direction, and extend in the X-axis direction across the inner wall surfaces of the first side wall 341 and the second side wall 342. The second flow path wall 352 is located in the Y2 direction of the first flow path wall 351. The first flow path wall 351 and the second flow path wall 352 face each other with a gap in between in the Y-axis direction.

[0023] The first partition wall 371 is a plate-like member extending in the Y1 direction from the center of the first flow path wall 351 in the X-axis direction. The tip of the first partition wall 371 faces the inner wall surface of the third side wall 343 with a gap therebetween. A supply port 321 is formed in the region of the second substrate 32 between the third side wall 343 and the first partition wall 371. The space between the inner wall surface of the third side wall 343 and the tip of the first partition wall 371 (hereinafter referred to as the "supply space Sa") communicates with the inside of the supply pipe 21 via the supply port 321. The supply space Sa is a space extending in the Y-axis direction between the first side wall 341 and the second side wall 342. As described above, the supply port 321 is provided in the supply space Sa.

[0024] A first space S1 is formed between the first partition 371 and the first side wall 341. A second space S2 is formed between the first partition 371 and the second side wall 342. The first space S1 and the second space S2 are spaces between the first substrate 31 and the second substrate 32. The second space S2 is located in the X2 direction of the first space S1. As can be understood from the above description, the first partition 371 is a partition that divides the space between the first substrate 31 and the second substrate 32 into the first space S1 and the second space S2.

[0025] The supply space Sa communicates with the first space S1 and the second space S2. Therefore, the refrigerant supplied from the supply pipe 21 to the supply space Sa through the supply port 321 is branched by the first partition wall 371 and supplied to the first space S1 and the second space S2. That is, the supply port 321 is shared between the first space S1 and the second space S2. Therefore, the structure of the cooling device 20 can be simplified compared to a configuration in which the supply ports 321 are individually provided for the first space S1 and the second space S2.

[0026] The second partition wall 372 is a plate-like member extending in the Y2 direction from the center of the second flow path wall 352 in the X-axis direction. The tip of the second partition wall 372 faces the inner wall surface of the fourth side wall 344 with a gap therebetween. A discharge port 322 is formed in the region of the second substrate 32 between the fourth side wall 344 and the second partition wall 372. The space between the inner wall surface of the fourth side wall 344 and the tip of the second partition wall 372 (hereinafter referred to as the "discharge space Sb") communicates with the inside of the discharge pipe 22 via the discharge port 322. The discharge space Sb is a space extending in the Y-axis direction between the first side wall 341 and the second side wall 342. As described above, the discharge port 322 is provided in the discharge space Sb.

[0027] A third space S3 is formed between the second partition wall 372 and the first side wall 341. A fourth space S4 is formed between the second partition wall 372 and the second side wall 342. The third space S3 and the fourth space S4 are spaces between the first substrate 31 and the second substrate 32. The third space S3 is located in the Y2 direction of the first space S1. The fourth space S4 is located in the Y2 direction of the second space S2. The fourth space S4 is located in the X2 direction of the third space S3. As can be understood from the above explanation, the second partition wall 372 is a partition that divides the space between the first substrate 31 and the second substrate 32 into the third space S3 and the fourth space S4.

[0028] The discharge space Sb communicates with the third space S3 and the fourth space S4. Therefore, the refrigerant that has passed through the third space S3 and the refrigerant that has passed through the fourth space S4 merge in the discharge space Sb, and the merged refrigerant passes through the discharge port 322 and is discharged to the discharge pipe 22. That is, the discharge port 322 is shared between the third space S3 and the fourth space S4. Therefore, the structure of the cooling device 20 can be simplified compared to a configuration in which the discharge ports 322 are individually provided for the third space S3 and the fourth space S4.

[0029] As illustrated above, the first space S1, the second space S2, the third space S3, and the fourth space S4 are located between the supply space Sa and the discharge space Sb. The first space S1 and the third space S3 are parallel to each other in the Y-axis direction and overlap with the first region C1 of the cooling surface C in a plan view. That is, the first circuit portion 11 located in the first region C1 is cooled by the refrigerant flowing through the first space S1 and the third space S3. On the other hand, the second space S2 and the fourth space S4 are parallel to each other in the Y-axis direction and overlap with the second region C2 of the cooling surface C in a plan view. The second circuit portion 12 located in the second region C2 is cooled by the refrigerant flowing through the second space S2 and the fourth space S4.

[0030] Fig. 6 is a cross-sectional view taken along line VI-VI in Fig. 4 and Fig. 5. Fig. 7 is a cross-sectional view taken along line VII-VII in Fig. 4 and Fig. 5. As illustrated in Figs. 4 to 7, the partition plate 36 is a plate-like member installed between the first flow path wall 351 and the second flow path wall 352. Specifically, the partition plate 36 is installed across the first flow path wall 351 and the second flow path wall 352 at the center of the internal space S in the Z-axis direction. Therefore, the space between the first flow path wall 351 and the second flow path wall 352 is partitioned in the Z-axis direction by the partition plate 36.

[0031] 4 and 5, the space between the first flow path wall 351 and the second flow path wall 352 is divided into a space located in the Z1 direction of the partition plate 36 (hereinafter referred to as a "first communication path P1") and a space located in the Z2 direction of the partition plate 36 (hereinafter referred to as a "second communication path P2"). The first communication path P1 and the second communication path P2 are flow paths that extend in the X-axis direction between the first side wall 341 and the second side wall 342. The first communication path P1 and the second communication path P2 are stacked in the Z-axis direction perpendicular to the cooling surface C. The first communication path P1 and the second communication path P2 are located between the set of the first space S1 and the second space S2 and the set of the third space S3 and the fourth space S4.

[0032] FIG. 8 is an enlarged perspective view of the vicinity of the first flow path wall 351. In FIG. 8, the first substrate 31 is omitted for convenience. As illustrated in FIGS. 6 and 8, the first flow path wall 351 has an opening Oa1 and an opening Oa2 formed therein. The opening Oa1 is a through-hole that connects the first space S1 and the first communication path P1. Specifically, the opening Oa1 is formed in a region of the first flow path wall 351 that is located further in the X1 direction than the first partition wall 371 and further in the Z1 direction than the partition plate 36. On the other hand, the opening Oa2 is a through-hole that connects the second space S2 and the second communication path P2. Specifically, the opening Oa2 is formed in a region of the first flow path wall 351 that is located further in the X2 direction than the first partition wall 371 and further in the Z2 direction than the partition plate 36.

[0033] 7, the second flow path wall 352 has openings Ob1 and Ob2 formed therein. The opening Ob1 is a through-hole that connects the fourth space S4 and the first communication passage P1. Specifically, the opening Ob1 is formed in a region of the second flow path wall 352 that is located further in the X2 direction than the second partition wall 372 and further in the Z1 direction than the partition plate 36. The opening Ob2 is a through-hole that connects the third space S3 and the second communication passage P2. Specifically, the opening Ob2 is formed in a region of the second flow path wall 352 that is located further in the X1 direction than the second partition wall 372 and further in the Z2 direction than the partition plate 36.

[0034] As illustrated in FIG. 4, the first space S1 communicates with the first communication passage P1 through the opening Oa1 of the first flow path wall 351, and the fourth space S4 communicates with the first communication passage P1 through the opening Ob1 of the second flow path wall 352. That is, the first space S1 and the fourth space S4 communicate with each other through the first communication passage P1. Therefore, as illustrated in FIG. 4, the refrigerant supplied from the supply space Sa to the first space S1 reaches the discharge space Sb through the first flow path F1 formed by the first space S1, the first communication passage P1, and the fourth space S4. That is, the refrigerant used to cool the first circuit portion 11 in the first space S1 moves to the fourth space S4 and is used to cool the second circuit portion 12.

[0035] On the other hand, as illustrated in Fig. 5, the second space S2 communicates with the second communication passage P2 through the opening Oa2 of the first flow path wall 351, and the third space S3 communicates with the second communication passage P2 through the opening Ob2 of the second flow path wall 352. That is, the second space S2 and the third space S3 communicate with each other through the second communication passage P2. Therefore, as illustrated in Fig. 5, the refrigerant supplied from the supply space Sa to the second space S2 reaches the discharge space Sb through the second flow path F2 formed by the second space S2, the second communication passage P2, and the third space S3. That is, the refrigerant used to cool the second circuit portion 12 in the second space S2 moves to the third space S3 and is used to cool the first circuit portion 11.

[0036] As described above, the internal space S of this embodiment includes the first space S1, the second space S2, the third space S3, the fourth space S4, the first communication passage P1, and the second communication passage P2. As can be seen from Figures 4 and 5, the first flow path F1 and the second flow path F2 intersect three-dimensionally midway through the flow paths. In the first embodiment, a simple configuration in which the first communication passage P1 and the second communication passage P2 are stacked in the Z-axis direction makes it possible to three-dimensionally intersect the first flow path F1, which includes the first space S1, the first communication passage P1, and the fourth space S4, and the second flow path F2, which includes the second space S2, the second communication passage P2, and the third space S3.

[0037] 4 and 5, a plurality of cooling fins 38 extending in the Y-axis direction are installed in each of the first space S1, the second space S2, the third space S3, and the fourth space S4. The plurality of cooling fins 38 are installed at intervals in the X-axis direction. The plurality of cooling fins 38 may be, for example, corrugated fins made by processing a metal plate into a wave shape.

[0038] The plurality of cooling fins 38 are installed, for example, on the surface of the first substrate 31 opposite to the cooling surface C. Heat propagated from the power conversion unit 10 to the first substrate 31 is dissipated from the plurality of cooling fins 38 to the refrigerant in the internal space S (S1 to S4). In other words, each of the plurality of cooling fins 38 is a heat exchanger that generates heat exchange with the refrigerant in the internal space S. As explained above, since the cooling fins 38 are installed in each of the spaces (S1 to S4) that make up the internal space S, efficient heat exchange can be achieved in each space.

[0039] FIG. 9 is a circuit diagram of the power conversion unit 10 in the first embodiment. The power conversion unit 10 in FIG. 9 is a semiconductor device including an inverter circuit 60. The inverter circuit 60 converts DC power supplied from a power supply (not shown) into AC power and supplies it to the electric motor 52. Specifically, the inverter circuit 60 includes a unit circuit 61u corresponding to the U phase, a unit circuit 61v corresponding to the V phase, and a unit circuit 61w corresponding to the W phase. Each unit circuit 61k (k=u, v, w) includes two switching elements 62k (62k_1, 62k_2) and two diodes 63k (63k_1, 63k_2). The capacitor 51 in FIG. 9 is installed between the power supply (not shown) and the inverter circuit 60 and smoothes the voltage supplied to the inverter circuit 60.

[0040] The switching element 62k_1 and the switching element 62k_2 are transistors connected in series between the positive terminal 64k and the negative terminal 65k. Each switching element 62k is configured, for example, with an IGBT (Insulated Gate Bipolar Transistor) or a MOSFET (Metal-Oxide-Semiconductor Field-Effect Transistor). The diode 63k_1 is connected in anti-parallel to the switching element 62k_1, and the diode 63k_2 is connected in anti-parallel to the switching element 62k_2. The positive terminal 64k of each unit circuit 61k is connected to the positive terminal 511 of the capacitor 51, and the negative terminal 65k of each unit circuit 61k is connected to the negative terminal 512 of the capacitor 51.

[0041] 10 is a plan view illustrating the positional relationship of the power conversion unit 10 (inverter circuit 60) with respect to the cooling surface C of the cooling device 20. As illustrated in Fig. 10, each unit circuit 61k in the first embodiment is configured by a semiconductor module 66k separate from each other. From the viewpoint of reducing the inductance of the wiring connecting the capacitor 51 and each unit circuit 61k, the positive terminal 64k and the negative terminal 65k of each unit circuit 61k are arranged in the direction of the Y axis along the edge of the power conversion unit 10 that is close to the capacitor 51.

[0042] Corresponding to the arrangement of the positive side terminals 64k and the negative side terminals 65k, the switching elements 62k (62k_1, 62k_2) of each unit circuit 61k are arranged in the Y-axis direction along an edge of the power conversion unit 10 located in the X1 direction. That is, the first circuit unit 11 installed in the first region C1 of the cooling surface C includes a plurality of switching elements 62k arranged in the Y-axis direction.

[0043] On the other hand, the diodes 63k (63k_1, 63k_2) of each unit circuit 61k are arranged in the Y-axis direction along an edge of the power conversion unit 10 located in the X2 direction. That is, the second circuit unit 12 installed in the second region C2 of the cooling surface C includes a plurality of diodes 63k arranged in the Y-axis direction.

[0044] 10, the first communication path P1 and the second communication path P2 are located between the pair of the switching element 62v_1 and the diode 63v_1 and the pair of the switching element 62v_2 and the diode 63v_2 in a plan view. In other words, the first communication path P1 and the second communication path P2 do not overlap the circuit elements (the switching element 62k and the diode 63k) of the power conversion unit 10 in a plan view.

[0045] FIG. 11 is an explanatory diagram of the effects of the first embodiment. FIG. 11 illustrates a comparative example for comparison with the first embodiment. In the comparative example, the first space S1 corresponding to the first region C1 of the cooling surface C communicates with the third space S3, and the second space S2 corresponding to the second region C2 communicates with the fourth space S4. As illustrated in FIG. 11, in the comparative example, the refrigerant flows linearly in the Y2 direction along the first flow path F1 that passes through the first space S1 and the third space S3, and the refrigerant flows linearly in the Y2 direction along the second flow path F2 that passes through the second space S2 and the fourth space S4.

[0046] That is, in the comparative example, the entire first flow path F1 corresponds to the first circuit portion 11 (first region C1) which generates a large amount of heat, and the entire second flow path F2 corresponds to the second circuit portion 12 (second region C2) which generates a small amount of heat. Therefore, the amount of increase in temperature of the refrigerant flowing through the first flow path F1 exceeds the amount of increase in temperature of the refrigerant flowing through the second flow path F2. That is, the temperature of the refrigerant increases significantly downstream of the first flow path F1, and as a result, there is a possibility that sufficient cooling performance cannot be maintained in the first region C1.

[0047] On the other hand, in the first embodiment, as described above, the first space S1 corresponding to the first region C1 and the fourth space S4 corresponding to the second region C2 are connected to each other, and the second space S2 corresponding to the second region C2 and the third space S3 corresponding to the first region C1 are connected to each other. That is, the upstream portion of the first flow path F1 corresponds to the first circuit portion 11, which generates a large amount of heat, while the downstream portion corresponds to the second circuit portion 12, which generates a small amount of heat. Therefore, the temperature rise of the refrigerant is suppressed in the downstream portion of the first flow path F1 compared to the upstream portion. Furthermore, the upstream portion of the second flow path F2 corresponds to the second circuit portion 12, which generates a small amount of heat, while the downstream portion corresponds to the first circuit portion 11, which generates a large amount of heat. Therefore, the temperature rise of the refrigerant is suppressed in the upstream portion of the second flow path F2 compared to the downstream portion.

[0048] As can be understood from the above description, according to the first embodiment, the difference between the temperature of the refrigerant downstream of the first flow path F1 and the temperature of the refrigerant downstream of the second flow path F2 is reduced (ideally eliminated) compared to the comparative example. That is, according to the first embodiment, the increase in the temperature of the refrigerant downstream of the first flow path F1 is suppressed, and as a result, sufficient cooling performance can be maintained downstream of both the first flow path F1 and the second flow path F2. For example, in the first embodiment, in a power conversion unit 10 including a plurality of switching elements 62k (62k_1, 62k_2) and a plurality of diodes 63k (63k_1, 63k_2), both the plurality of switching elements 62k and the plurality of diodes 63k can be effectively cooled.

[0049] B: Second embodiment A second embodiment will be described. Note that, for elements in the following exemplary aspects that have the same functions as those in the first embodiment, the same reference numerals as those in the first embodiment will be used, and detailed descriptions of each will be omitted as appropriate.

[0050] FIG. 12 is an explanatory diagram of the positional relationship between the cooling device 20 and the power conversion unit 10 in the second embodiment. The power conversion unit 10 in the second embodiment is a semiconductor device including an inverter circuit 60 similar to that in the first embodiment. However, in the inverter circuit 60 in the second embodiment, a unit circuit 61u, a unit circuit 61v, and a unit circuit 61w are configured as a single semiconductor module 66. The semiconductor module 66 includes a positive terminal 64 and a negative terminal 65. The positive terminal 64 and the negative terminal 65 are arranged in the direction of the Y-axis along an edge of the power conversion unit 10 that is closer to the capacitor 51. The switching elements 62k_1 of each unit circuit 61k are commonly connected to the positive terminal 64, and the switching elements 62k_2 of each unit circuit 61k are commonly connected to the negative terminal 65.

[0051] In order to correspond to the arrangement of the positive side terminals 64 and the negative side terminals 65, the switching elements 62k (62k_1, 62k_2) of each unit circuit 61k are arranged in the Y-axis direction along an edge of the power conversion unit 10 located in the X1 direction. That is, similar to the first embodiment, the first circuit unit 11 installed in the first region C1 of the cooling surface C includes a plurality of switching elements 62k arranged in the Y-axis direction.

[0052] On the other hand, the diodes 63k (63k_1, 63k_2) of each unit circuit 61k are arranged in the Y-axis direction along an edge of the power conversion unit 10 located in the X2 direction. That is, the second circuit unit 12 installed in the second region C2 of the cooling surface C includes a plurality of diodes 63k arranged in the Y-axis direction. As can be understood from the above description, the second embodiment also achieves the same effects as the first embodiment.

[0053] C: Third embodiment Fig. 13 is a circuit diagram of a power conversion unit 10 according to the third embodiment. The power conversion unit 10 according to the third embodiment is a semiconductor device including an inverter circuit 71 and a converter circuit 72. The converter circuit 72 converts AC power supplied from the power grid 53 into DC power using a reactor (not shown) installed between the power grid 53 and the converter circuit 72. The inverter circuit 71 converts the DC power converted by the converter circuit 72 into AC power of a predetermined frequency. A capacitor 75 shown in Fig. 13 is installed between the inverter circuit 71 and the converter circuit 72, and smooths the voltage supplied to the inverter circuit 71.

[0054] The voltage value and frequency differ between the inverter circuit 71 and the converter circuit 72. Therefore, the amount of heat generated by the inverter circuit 71 differs from the amount of heat generated by the converter circuit 72. One of the inverter circuit 71 and the converter circuit 72 is an example of a "first power conversion circuit," and the other is an example of a "second power conversion circuit."

[0055] The inverter circuit 71 includes two circuit elements 73k (73k_1, 73k_2) corresponding to the U, V, and W phases, respectively. Similarly, the converter circuit 72 includes two circuit elements 74k (74k_1, 74k_2) corresponding to the U, V, and W phases, respectively. Each circuit element 73k and each circuit element 74k is a pair of a switching element and a diode connected in anti-parallel to each other.

[0056] 14 is an explanatory diagram of the positional relationship between the cooling device 20 and the power conversion unit 10 in the third embodiment. The circuit elements 73k (73k_1, 73k_2) of the inverter circuit 71 are arranged in the Y-axis direction along an edge of the power conversion unit 10 located in the X1 direction. That is, the first circuit unit 11 installed in the first region C1 of the cooling surface C includes a plurality of circuit elements 73k arranged in the Y-axis direction. As described above, the first circuit unit 11 is the inverter circuit 71 of the power conversion unit 10. The circuit element 73k is an example of a "first circuit element."

[0057] On the other hand, the circuit elements 74k (74k_1, 74k_2) of the converter circuit 72 are arranged in the Y-axis direction along an edge of the power conversion unit 10 located in the X2 direction. That is, the second circuit unit 12 installed in the second region C2 of the cooling surface C includes a plurality of circuit elements 74k arranged in the Y-axis direction. As described above, the second circuit unit 12 is the converter circuit 72 of the power conversion unit 10. The circuit element 74k is an example of a "second circuit element."

[0058] 14, the first communication path P1 and the second communication path P2 are located between the pair of circuit elements 73v_1 and 74v_1 and the pair of circuit elements 73v_2 and 74v_2 in a plan view. In other words, the first communication path P1 and the second communication path P2 do not overlap with the circuit elements (73k, 74k) of the power conversion unit 10 in a plan view.

[0059] The third embodiment also achieves the same effects as the first embodiment. Moreover, in the third embodiment, in the power conversion unit 10 including a plurality of circuits (the inverter circuit 71 and the converter circuit 72) with different functions, both the plurality of circuit elements 73k and the plurality of circuit elements 74k can be effectively cooled.

[0060] Although the third embodiment illustrates a combination of the inverter circuit 71 and the converter circuit 72, the combination of circuits constituting the power conversion unit 10 is not limited to the above example. For example, even in a configuration in which the power conversion unit 10 is configured with a combination of a chopper circuit and an inverter circuit, a configuration similar to that of the third embodiment is adopted. That is, for example, one of the chopper circuit and the inverter circuit is installed in the first area C1 as the first circuit unit 11, and the other is installed in the second area C2 as the second circuit unit 12. As can be understood from the above example, the first power conversion circuit and the second power conversion circuit are collectively expressed as circuits with different functions, and the specific configuration or function of each is not important.

[0061] D: Fourth embodiment Fig. 15 is a circuit diagram of the power conversion unit 10 in the fourth embodiment. The power conversion unit 10 in the third embodiment is a semiconductor device including an inverter circuit 81 and a chopper circuit 82. The chopper circuit 82 converts the voltage value of the DC voltage supplied from the power supply 54. The inverter circuit 81 converts the DC voltage converted by the chopper circuit 82 into an AC voltage of a predetermined frequency and supplies it to the electric motor 52. The capacitor 86 in Fig. 15 is installed between the inverter circuit 81 and the chopper circuit 82 and smoothes the voltage supplied to the inverter circuit 81.

[0062] As in the third embodiment, the inverter circuit 81 includes two circuit elements 83k (83k_1, 83k_2) corresponding to the U, V, and W phases, respectively. The chopper circuit 82 includes a passive component 84 and two circuit elements 85 (85_1, 85_2). Each circuit element 83k and each circuit element 85 is a pair of a switching element and a diode connected in anti-parallel to each other. The passive component 84 is, for example, an inductor.

[0063] 16 is an explanatory diagram of the positional relationship between the cooling device 20 and the power conversion unit 10 in the fourth embodiment. The circuit elements 83k (83k_1, 83k_2) of the inverter circuit 81 and the circuit elements 85 (85_1, 85_2) of the chopper circuit 82 are arranged in the Y-axis direction along an edge of the power conversion unit 10 located in the X1 direction. That is, the first circuit unit 11 installed in the first region C1 of the cooling surface C includes a plurality of circuit elements 85 arranged in the Y-axis direction.

[0064] 16, the first communication path P1 and the second communication path P2 are located between the circuit element 83u_2 and the circuit element 83v_1 in a plan view. That is, the first communication path P1 and the second communication path P2 do not overlap with the circuit elements (83k, 85) of the power conversion unit 10 in a plan view.

[0065] The passive components 84 of the chopper circuit 82 are elongated components. The passive components 84 are arranged along the edge of the power conversion unit 10 located in the X2 direction. That is, the second circuit unit 12 installed in the second region C2 of the cooling surface C includes a passive component 84 that is elongated in the Y-axis direction. As illustrated in FIG. 16 , the passive components 84 overlap the first communication path P1 and the second communication path P2 in a plan view.

[0066] The fourth embodiment also achieves the same effects as the first embodiment. Moreover, in the fourth embodiment, it is possible to effectively cool both the passive component 84 and the plurality of circuit elements 85 in the chopper circuit 82. Note that the passive component 84 cooled by the cooling device 20 is not limited to an inductor, and may be other components such as a capacitor.

[0067] E: Modified Example Specific modified embodiments that can be added to each of the embodiments exemplified above are exemplified below. Two or more embodiments arbitrarily selected from the following examples may be combined as appropriate within the scope of not being mutually contradictory.

[0068] (1) In the above-described embodiments, the spaces (S1 to S4) constituting the internal space S have the same shape, but the shapes (cross-sectional area, overall length, volume, etc.) of the spaces (S1 to S4) may be different. In addition, in the above-described embodiments, the first communication passage P1 and the second communication passage P2 are located in the center of the internal space S in the Y-axis direction, but the positions of the first communication passage P1 and the second communication passage P2 are arbitrary.

[0069] For example, as illustrated in Fig. 17, in a configuration in which the overall lengths of the first space S1 and the second space S2 are shorter than the overall lengths of the third space S3 and the fourth space S4, the first communication passage P1 and the second communication passage P2 are formed at a position closer to the supply space Sa than to the discharge space Sb. Also, as illustrated in Fig. 18, in a configuration in which the overall lengths of the third space S3 and the fourth space S4 are shorter than the overall lengths of the first space S1 and the second space S2, the first communication passage P1 and the second communication passage P2 are formed at a position closer to the discharge space Sb than to the supply space Sa.

[0070] (2) In each of the above-described embodiments, the first communication passage P1 and the second communication passage P2 do not overlap the circuit elements of the power conversion unit 10 in a planar view. However, the first communication passage P1 and the second communication passage P2 may overlap the circuit elements of the power conversion unit 10 in a planar view.

[0071] (3) In the above-described embodiments, the cooling fins 38 are not provided in the first communication passage P1 and the second communication passage P2. However, the cooling fins 38 may also be provided in the first communication passage P1 and the second communication passage P2. However, since it is difficult to ensure the flow path area of ​​each of the first communication passage P1 and the second communication passage P2 when the first communication passage P1 and the second communication passage P2 are stacked in the Z-axis direction, a configuration in which the cooling fins 38 are not provided in the first communication passage P1 and the second communication passage P2 is preferable. Note that in a configuration in which the cooling fins 38 are not provided in the first communication passage P1 and the second communication passage P2, as exemplified in the above-described embodiments, a configuration in which the first communication passage P1 and the second communication passage P2 do not overlap the circuit elements of the power conversion unit 10 in a plan view is preferable.

[0072] (4) In the above-described embodiments, the amount of heat generated by the first circuit unit 11 exceeds the amount of heat generated by the second circuit unit 12. However, an embodiment in which the amount of heat generated by the second circuit unit 12 exceeds the amount of heat generated by the first circuit unit 11 is also contemplated. An embodiment in which the amount of heat generated by the first circuit unit 11 and the amount of heat generated by the second circuit unit 12 change over time is also contemplated. For example, during a first period in which the power conversion unit 10 operates, the amount of heat generated by the first circuit unit 11 exceeds the amount of heat generated by the second circuit unit 12, and during a second period different from the first period, the amount of heat generated by the second circuit unit 12 exceeds the amount of heat generated by the first circuit unit 11.

[0073] (5) In each of the above-described embodiments, a configuration in which a plurality of cooling fins 38 are installed in the internal space S (S1 to S4) has been described as an example, but the heat exchanger that generates heat exchange with the refrigerant is not limited to the cooling fins 38. For example, columnar pin fins that protrude in the Z1 direction from the surface of the first substrate 31 in the Z1 direction may be installed as the heat exchanger.

[0074] (6) In the above-described embodiments, the plurality of cooling fins 38 are arranged at equal intervals. However, as illustrated in FIG. 19, a configuration is also conceivable in which the intervals between the plurality of cooling fins 38 vary depending on the position in the X-axis direction. In the configuration of FIG. 19, the intervals between the cooling fins 38 at the center of the first space S1 in the X-axis direction are smaller than the intervals between the cooling fins 38 at the ends of the first space S1 in the X-axis direction. That is, the cooling fins 38 are arranged more densely near the center of the first space S1 in the X-axis direction than near the first side wall 341 or the first partition wall 371 in the first space S1. Note that, although the above description has focused on the first space S1 for convenience, the intervals between the plurality of cooling fins 38 in the other spaces (S2 to S4) of the internal space S also vary depending on the position in the arrangement direction (i.e., the Y-axis direction).

[0075] (7) In each of the above-described embodiments, the cooling device 20 cools the power conversion unit 10, but the heat-generating element to be cooled by the cooling device 20 is not limited to the power conversion unit 10. The cooling device 20 exemplified in each of the above-described embodiments may be used to cool any type of heat-generating element.

[0076] (8) In the above-described embodiments, the heat generating element (power conversion unit 10) is installed on the cooling surface C of the first substrate 31 of the housing 30. However, in addition to the cooling surface C of the first substrate 31, the surface of the second substrate 32 in the Z1 direction may also be used as a cooling surface for cooling the heat generating element. That is, the power conversion unit 10 may be installed on the surface of the second substrate 32 in the Z1 direction.

[0077] (9) The term "nth" (n is a natural number) in this application is used only as a formal and convenient label to distinguish each element in the description and does not have any substantive meaning. Therefore, there is no room for restrictive interpretation of the position of each element or the order of manufacture, etc., based on the term "nth."

[0078] F: Notes From the above-described exemplary embodiments, the following configurations can be understood, for example.

[0079] A cooling device according to one aspect (aspect 1) of the present disclosure is a cooling device including a cooling surface extending along a first direction and a second direction that intersect with each other, and an internal space through which a refrigerant that cools the cooling surface flows, wherein the internal space includes a first space, a second space located in the first direction of the first space, a third space located in the second direction of the first space, a fourth space located in the second direction of the second space, a first communication passage connecting the first space and the fourth space, and a second communication passage connecting the second space and the third space.

[0080] In the above configuration, assume that a first heating element is installed in a first region of the cooling surface corresponding to the first space and the third space, and a second heating element is installed in a second region of the cooling surface corresponding to the second space and the fourth space. The amount of heat generated by the first heating element exceeds the amount of heat generated by the second heating element. The refrigerant in the internal space flows through a first flow path extending from the first space to the fourth space via a first communication path and a second flow path extending from the second space to the third space via a second communication path. The refrigerant flowing through the first flow path cools the first heating element in the first region in the first space and cools the second heating element in the second region in the fourth space. On the other hand, the refrigerant flowing through the second flow path cools the second heating element in the second region in the second space and cools the first heating element in the first region in the third space. Therefore, compared to a configuration in which the first space and the third space are connected and the second space and the fourth space are connected, the difference in temperature between the refrigerant downstream of the first flow path and the refrigerant downstream of the second flow path is reduced. That is, the rise in the temperature of the coolant downstream of the first flow path is suppressed, and as a result, sufficient cooling performance can be maintained downstream of both the first flow path and the second flow path.

[0081] In a specific example (Aspect 2) of Aspect 1, the first communication passage and the second communication passage are stacked in a third direction perpendicular to the cooling surface, between the set of the first space and the second space and the set of the third space and the fourth space. In the above aspect, the simple configuration of stacking the first communication passage and the second communication passage makes it possible to three-dimensionally intersect a first flow path including the first space, the first communication passage, and the fourth space, and a second flow path including the second space, the second communication passage, and the third communication passage.

[0082] In a specific example (Aspect 3) of Aspect 1 or Aspect 2, the internal space further includes a supply space having a refrigerant supply port and communicating with the first space and the second space, and a discharge space having a refrigerant discharge port and communicating with the third space and the fourth space. In the above aspect, the refrigerant supplied from the supply port to the supply space branches into the first space and the second space. That is, the supply port is shared between the first space and the second space. Therefore, the structure of the cooling device can be simplified compared to an embodiment in which supply ports are provided individually for the first space and the second space. Furthermore, the refrigerant that has passed through the third space and the refrigerant that has passed through the fourth space join in the discharge space, and the joined refrigerant is discharged from the discharge port. That is, the discharge port is shared between the third space and the fourth space. Therefore, the structure of the cooling device can be simplified compared to an embodiment in which discharge ports are provided individually for the third space and the fourth space.

[0083] A specific example (Aspect 4) of any one of Aspects 1 to 3 further includes a heat exchange element installed in each of the first space, the second space, the third space, and the fourth space. In the above aspects, a heat exchange element is installed in each space that constitutes the internal space, so that efficient heat exchange can be achieved in each space.

[0084] A power conversion device according to one aspect (aspect 5) of the present disclosure comprises a power conversion section including a first circuit section and a second circuit section having different heat generation amounts, a cooling device including a cooling surface along a first direction and a second direction that intersect each other, and an internal space through which a refrigerant that cools the cooling surface flows, wherein the cooling surface includes a first region extending in the second direction and in which the first circuit section is installed, and a second region extending in the second direction in the first direction of the first region and in which the second circuit section is installed, and the internal space includes a first space corresponding to the first region, a second space corresponding to the second region and located in the first direction of the first space, a third space corresponding to the first region and located in the second direction of the first space, a fourth space corresponding to the second region and located in the second direction of the second space, a first communication passage connecting the first space and the fourth space, and a second communication passage connecting the second space and the third space. According to the above aspect, the difference in temperature between the refrigerant downstream of the first flow path and the refrigerant downstream of the second flow path is reduced, that is, the increase in the refrigerant temperature downstream of the first flow path is suppressed, and as a result, sufficient cooling performance can be maintained downstream of both the first flow path and the second flow path.

[0085] In a specific example (Aspect 6) of Aspect 5, the first circuit section includes a plurality of switching elements arranged in the second direction, and the second circuit section includes a plurality of diodes arranged in the second direction. According to the above aspect, it is possible to effectively cool both the plurality of switching elements and the plurality of diodes in the power conversion device.

[0086] In a specific example (Aspect 7) of Aspect 5, the first circuit section includes a first power conversion circuit including a plurality of first circuit elements arranged in the second direction, and the second circuit section includes a second power conversion circuit including a plurality of second circuit elements arranged in the second direction and having a function different from that of the first power conversion circuit. With the above configuration, it is possible to effectively cool both the plurality of first circuit elements of the first power conversion circuit and the plurality of second circuit elements of the second power conversion circuit.

[0087] In a specific example (Aspect 8) of Aspect 5, the first circuit section includes a passive component that is elongated in the second direction, and the second circuit section includes a plurality of circuit elements arranged in the second direction. With this configuration, both the plurality of circuit elements and the passive components in the power conversion section can be effectively cooled. [Explanation of symbols]

[0088] 100...power conversion device, 10...power conversion section, 11...first circuit section, 12...second circuit section, 20...cooling device, 21...supply pipe, 22...discharge pipe, 30...casing, 31...first substrate, 32...second substrate, 321...supply port, 322...discharge port, 34...outer wall section, 341...first side wall, 342...second side wall, 343...third side wall, 344...fourth side wall, 351...first flow path wall, 352...second 2. Flow path wall, 36...partition plate, 371...first partition wall, 372...second partition wall, 51, 75, 86...condenser, S...internal space, S1...first space, S2...second space, S3...third space, S4...fourth space, Sa...supply space, Sb...discharge space, P1...first communication path, P2...second communication path, F1...first flow path, F2...second flow path, C...cooling surface, C1...first region, C2...second region.

Claims

1. A cooling device including a cooling surface along a first direction and a second direction intersecting each other, and an internal space through which a refrigerant for cooling the cooling surface flows, The internal space is A first space; a second space located in the first direction of the first space; a third space located in the second direction of the first space; a fourth space located in the second direction of the second space; a first communication passage that communicates the first space with the fourth space; a second communication passage that connects the second space and the third space Cooling device.

2. The first communication passage and the second communication passage are stacked in a third direction perpendicular to the cooling surface between the set of the first space and the second space and the set of the third space and the fourth space. The cooling device of claim 1.

3. The internal space is a supply space in which a refrigerant supply port is provided and which communicates with the first space and the second space; a discharge space in which a refrigerant discharge port is provided and which communicates with the third space and the fourth space; The cooling device of claim 1 or claim 2, further comprising:

4. a heat exchange element disposed in each of the first space, the second space, the third space, and the fourth space; The cooling device of claim 1 further comprising:

5. a power conversion unit including a first circuit unit and a second circuit unit that generate different amounts of heat; a cooling device including a cooling surface along a first direction and a second direction intersecting each other, and an internal space through which a refrigerant for cooling the cooling surface flows; The cooling surface is a first region extending in the second direction and in which the first circuit portion is disposed; a second region extending in the second direction in the first direction of the first region and in which the second circuit portion is provided, The internal space is a first space corresponding to the first region; a second space corresponding to the second region and positioned in the first direction of the first space; a third space corresponding to the first region and positioned in the second direction of the first space; a fourth space corresponding to the second region and positioned in the second direction of the second space; a first communication passage that communicates the first space with the fourth space; a second communication passage that connects the second space and the third space Power conversion device.

6. the first circuit portion includes a plurality of switching elements arranged in the second direction, The second circuit portion includes a plurality of diodes arranged in the second direction. The power converter of claim 5.

7. the first circuit section includes a first power conversion circuit including a plurality of first circuit elements arranged in the second direction; The second circuit section includes a plurality of second circuit elements arranged in the second direction, and includes a second power conversion circuit having a function different from that of the first power conversion circuit. The power converter of claim 5.

8. the first circuit portion includes a passive component that is elongated in the second direction, The second circuit portion includes a plurality of circuit elements arranged in the second direction. The power converter of claim 5.

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