Power conversion device

Abstract

To provide a power conversion device in which bubbles mixed in a cooling liquid are unlikely to accumulate in a portion of a cooling flow path facing an electronic component even when the flow rate of the cooling liquid is low.SOLUTION: A power conversion device includes a plurality of electronic components 66a, 70a and cooling plates 11, 12 through which a cooling liquid flows to cool the plurality of electronic components 66a, 70a, the plurality of electronic components 66a, 70a include at least a first cooling target 66a and a second cooling target 70a, the cooling plates 11, 12 include a first flow path 11C formed in a horizontal direction to cool the first cooling target 66a, and a second flow path 11D arranged downstream of the first flow path 11C to cool the second cooling target 70a, the second flow path 11D is located above the first flow path 11C and includes a bubble trapping portion 80 capable of storing bubbles P while allowing the cooling liquid to flow.SELECTED DRAWING: Figure 6

Description

[Technical Field]

[0001] The present invention relates to a power conversion device. [Background technology]

[0002] In recent years, automobiles equipped with motors as a driving source (such as hybrid electric vehicles (HEVs), plug-in hybrid electric vehicles (PHEVs), battery electric vehicles (BEVs), and fuel cell electric vehicles (FCEVs)) have become widespread. These automobiles are equipped with a vehicle drive system that drives the motor and other components, and this vehicle drive system is equipped with a power conversion device having a plurality of electronic components.

[0003] Patent Document 1, cited below, describes a power conversion device. This power conversion device includes a semiconductor module that constitutes a power conversion circuit and a cooling case that cools the semiconductor module with a refrigerant, and is configured so that the semiconductor module, which is arranged on the upper wall surface of the cooling case, can be cooled by the refrigerant. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2011-217553 Summary of the Invention [Problem to be solved by the invention]

[0005] In the power converter described in Patent Document 1, air bubbles may flow into the flow paths formed inside the cooling case along with the refrigerant. These air bubbles may accumulate below the upper wall surface of the flow path facing the semiconductor module, reducing the cooling efficiency of the semiconductor module. Therefore, in the power converter described in Patent Document 1, the refrigerant inlet pipe and refrigerant outlet pipe connected to the cooling case are positioned above the upper wall surface of the cooling case. This makes it difficult for air bubbles to accumulate in the cooling case.

[0006] However, in the power converter described in Patent Document 1, when the flow rate of the coolant is low, there is still a risk that air bubbles may remain on the upper wall surface of the cooling case, and there is room for improvement.

[0007] Therefore, there is a demand for a power converter in which bubbles mixed in the coolant are less likely to accumulate in the portion of the cooling flow path facing the electronic components even when the flow rate of the coolant is low. [Means for solving the problem]

[0008] One embodiment of a power conversion device according to the present invention comprises a plurality of electronic components and a cooling plate through which a cooling liquid flows to cool the plurality of electronic components, the plurality of electronic components including at least a first cooling target and a second cooling target, the cooling plate including a first flow path formed horizontally to cool the first cooling target, and a second flow path arranged downstream of the first flow path to cool the second cooling target, the second flow path being located above the first flow path and having an air bubble trapping portion capable of storing air bubbles while allowing the cooling liquid to flow.

[0009] According to this configuration, even if air bubbles are mixed into the coolant when the coolant cools the first cooling target and the second cooling target in that order, the air bubbles can be trapped in the air bubble trap located above the first flow path that cools the first cooling target. Therefore, for example, by positioning the first cooling target at a position other than the air bubble trap, the first cooling target and the second cooling target can be reliably cooled by the coolant flowing through the cooling plate. Furthermore, because the air bubble trap can trap air bubbles while allowing the coolant to flow, even if air bubbles remain trapped in the air bubble trap due to the slow flow velocity of the coolant, they do not impede the flow of the coolant. This achieves a power conversion device capable of effectively cooling multiple electronic components. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a longitudinal cross-sectional view of a vehicle drive device accommodating a conversion module. [Figure 2] FIG. 1 is a perspective view of a power conversion device. [Figure 3] FIG. 2 is a cooling circuit diagram showing a cooling fluid flow path and a refrigerant flow path. [Figure 4] FIG. 4 is a cross-sectional view taken along the line IV-IV in FIG. [Figure 5] FIG. 2 is a cross-sectional view taken along the arrows VV in FIG. [Figure 6] FIG. 2 is a partial cross-sectional view of the cooling plate in the first embodiment. [Figure 7] FIG. 10 is a partial cross-sectional view of a cooling plate of a comparative example. [Figure 8] FIG. 10 is a partial cross-sectional view of a modified example of the cooling plate. [Figure 9] FIG. 10 is a partial cross-sectional view of a cooling plate in a second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, an embodiment of a cooling channel structure according to the present invention will be described with reference to the drawings. In this embodiment, the cooling channel structure cools a plurality of electronic components arranged in a power conversion device B. However, the present invention is not limited to the following embodiment, and various modifications are possible within the scope of the present invention.

[0012] [Basic configuration] Fig. 1 shows a vehicle drive device A that transmits the driving force of a traction motor M to the drive wheels (not shown) of a vehicle. This vehicle drive device A accommodates the traction motor M, a gear mechanism Ge that reduces the driving force of the traction motor M and transmits it to the drive wheels, a power conversion device B, and an inverter C in a housing AH. Hereinafter, a vehicle equipped with a traction motor M as a driving source will also be referred to as an electric vehicle. Examples of electric vehicles include hybrid electric vehicles (HEVs), plug-in hybrid electric vehicles (PHEVs), battery electric vehicles (BEVs), and fuel cell electric vehicles (FCEVs).

[0013] The vehicle drive device A is provided in the electric vehicle 100 in the vertical relationship shown in Fig. 1, and therefore in this embodiment, the vertical relationship will be described in accordance with the vertical direction shown in Fig. 1. Also, Fig. 1 shows a vertical cross section of the vehicle drive device A as seen in the front-rear direction, and the left-right direction in Fig. 1 corresponds to the width direction of the vehicle body.

[0014] Power conversion device B converts AC power from an AC power source (basically a commercial power source) supplied from outside electric vehicle 100 into high-voltage DC power. The converted high-voltage DC power is charged into a main battery (not shown) arranged outside vehicle drive device A. Power conversion device B can also convert DC power from the main battery to generate AC power similar to that of the commercial power source and supply it to the outside of electric vehicle 100.

[0015] The inverter C converts DC power from the main battery into three-phase AC power, controls the frequency, and supplies it to the traction motor M. This drives the drive wheels of the electric vehicle 100, causing the electric vehicle 100 to travel.

[0016] 1 and 2, the power conversion device B is configured with multiple layers in which multiple conversion modules (first conversion module Ba, second conversion module Bb, and third conversion module Bc) are arranged in an overlapping manner in the vertical direction. The inverter C is provided above the power conversion device B.

[0017] [Vehicle drive device] As shown in Fig. 1, the vehicle drive device A accommodates a travel motor M and a gear mechanism Ge in a lower space LS of a housing AH. In the vehicle drive device A, the outer side of the travel motor M in the lower space LS is closed by a motor cover 1, and the outer side of the gear mechanism Ge in the lower space LS is closed by a gear cover 2. The rotation axis A1 of the travel motor M is coaxial with the rotation axis of the gear mechanism Ge.

[0018] The vehicle drive device A accommodates a power conversion device B and an inverter C in an upper space HS of a housing AH. This upper space HS is closed by an upper cover 3. The lower space LS and the upper space HS are independent spaces that do not communicate with each other.

[0019] As shown in Figure 1, the power conversion device B has multiple layers in which multiple conversion modules (a first conversion module Ba, a second conversion module Bb, and a third conversion module Bc) are arranged in a stacked state, and an inverter C is provided on the upper surface of the power conversion device B.

[0020] In this embodiment, as described above, the power conversion device B and the inverter C are housed in an integrated state inside the housing AH of the vehicle drive device A, but the power conversion device B may be separated from the inverter C. Furthermore, the vehicle drive device A is configured to house both the power conversion device B and the inverter C inside, but at least one of the power conversion device B and the inverter C may be disposed on the outer wall surface of the housing AH of the vehicle drive device A or outside.

[0021] [Layer structure of power conversion device] 1 and 2, the power conversion device B has a first conversion module Ba, a second conversion module Bb, and a third conversion module Bc arranged in this order from top to bottom. The power conversion device B has a first cooling plate 11 (an example of a cooling plate) arranged on the upper stage, and a second cooling plate 12 (an example of a cooling plate) arranged below it at a set distance, and these are connected via a spacer or the like to maintain the set distance between the first cooling plate 11 and the second cooling plate 12.

[0022] Specifically, the power conversion device B has a first conversion module Ba and a second conversion module Bb arranged below the first cooling plate 11 and above the second cooling plate 12, and a third conversion module Bc arranged below the second cooling plate 12. Furthermore, the inverter C is arranged above the first cooling plate 11.

[0023] The first conversion module Ba is composed of a plurality of switching elements 15 (an example of electronic components) mounted on the upper surface of a plate-shaped upper substrate 14. The upper substrate 14 is supported by the first cooling plate 11 while being spaced downward from the first cooling plate 11. The plurality of switching elements 15 constitute a part of an OBC (On Board Charger) unit.

[0024] 1, a plurality of switching elements 15 are shown as one block. These switching elements 15 are arranged in contact with or in close proximity to the lower surface of the first cooling plate 11.

[0025] 1, the second conversion module Bb is composed of a transformer T mounted on the lower surface of an upper substrate 14, a plurality of bulk capacitors 16, and a frame member 18. The frame member 18 functions as a spacer by protruding downward from the lower surface of the upper substrate 14 while surrounding at least a portion of the outer periphery of the transformer T.

[0026] As shown in FIG. 1, the third conversion module Bc includes a plurality of coil modules 21 and a plurality of AC filters 22 on the upper surface of a lower substrate 20 that is arranged below and separated from the lower surface of the second cooling plate 12.

[0027] The upper surfaces of the plurality of coil modules 21 and the upper surfaces of the plurality of AC filters 22 are arranged in contact with or in close proximity to the lower surface of the second cooling plate 12.

[0028] [Cooling circuit] 3, the vehicle drive device A includes a cooling circuit including a coolant flow path L1 for circulating a coolant as a cooling fluid, a refrigerant flow path L2 for circulating a refrigerant, and a lubricant flow path L3 for circulating a lubricant. The cooling fluid in this embodiment is composed of a coolant (hereinafter referred to as "coolant") such as a long-life coolant (LLC) containing ethylene glycol or propylene glycol, or insulating oil.

[0029] The coolant flow path L1 circulates the coolant through the first cooling plate 11 and second cooling plate 12 of the power conversion device B, the oil cooler 32, the water-cooled condenser 31, and the radiator 34 in this order by driving the coolant pump 33. A flow path R, which will be described later, is a part of the coolant flow path L1.

[0030] The refrigerant flow path L2 is configured to supply an externally cooled refrigerant to the water-cooled condenser 31. In this refrigerant flow path L2, a hydrofluorocarbon (HFC), a hydrofluoroolefin (HFO), or the like is used as the refrigerant.

[0031] The lubricating oil passage L3 supplies low-temperature lubricating oil to the inside of the traveling motor M and the gear mechanism Ge when the hydraulic pump 35 is driven.

[0032] In this cooling circuit, the coolant cooled by the radiator 34 flows through the flow path R of the first cooling plate 11 and the flow path R of the second cooling plate 12 of the power conversion device B. As a result, the coolant absorbs heat generated in the first conversion module Ba, the second conversion module Bb, and the third conversion module Bc, and cools the first conversion module Ba, the second conversion module Bb, and the third conversion module Bc. As a result, the temperature of the coolant rises.

[0033] The oil cooler 32 is disposed downstream of the power converter B in the coolant flow path L1, and exchanges heat between the oil and the coolant circulating through the coolant flow path L1. This further increases the temperature of the coolant and decreases the temperature of the oil. The oil with the decreased temperature is then circulated through the lubricant flow path L3. This suppresses the temperature increase of the drive motor M and gear mechanism Ge in the lower space LS of the housing AH, and lubricates the drive motor M and gear mechanism Ge. The coolant whose temperature has increased in the oil cooler 32 absorbs heat from the refrigerant in the water-cooled condenser 31, then its temperature is reduced by heat dissipation in the radiator 34, and it is then supplied to the power converter B again.

[0034] [Cooling mechanism] The power conversion device B is cooled by a coolant flowing through the first cooling plate 11 and the second cooling plate 12. As shown in Fig. 1, the first cooling plate 11 and the second cooling plate 12 are configured such that a flow path R is continuous between the first cooling plate 11 and the second cooling plate 12 by a communication path 13 extending in the vertical direction.

[0035] The coolant cooled by the radiator 34 or the like and reaching the power converter B flows into the flow path R of the second cooling plate 12 from the inlet 17 of the second cooling plate 12 shown in FIG. 5. The second cooling plate 12 has a first portion 12A, a second portion 12B, a third portion 12C, and a fourth portion 12D formed in series. The flow path R is formed so that the coolant flows through the first portion 12A, the second portion 12B, the third portion 12C, and the fourth portion 12D in this order. The first portion 12A extends in the longitudinal direction of the lower substrate 20 (see FIG. 1 ; the same applies below). The second portion 12B is folded back from an end of the first portion 12A and extends in a curved manner. The third portion 12C is folded back from an end of the second portion 12B and extends in the longitudinal direction of the lower substrate 20. The fourth portion 12D is folded back from an end of the third portion 12C and extends in the longitudinal direction of the lower substrate 20. An end of the fourth portion 12D is connected to an end of the communication passage 13.

[0036] The coolant that has flowed through the flow path R formed in the communication path 13 reaches the first cooling plate 11. As shown in FIG. 4, the first cooling plate 11 has a first portion 11A, a second portion 11B, a third portion 11C (an example of a first flow path), a fourth portion 11D (an example of a second flow path), and a fifth portion 11E formed in succession. The flow path R is formed so that the coolant flows through the first portion 11A, the second portion 11B, the third portion 11C, the fourth portion 11D, and the fifth portion 11E in this order. The first portion 11A extends in the longitudinal direction of the lower substrate 20. The second portion 11B is folded back from an end of the first portion 11A and extends in the longitudinal direction of the lower substrate 20. The third portion 11C is folded back from an end of the second portion 11B and extends in the longitudinal direction of the lower substrate 20. The fourth portion 11D extends from the end of the third portion 11C by folding back at a right angle to the longitudinal direction of the lower substrate 20. The fifth portion 11E extends from the end of the fourth portion 11D by folding back in the longitudinal direction of the lower substrate 20. An outlet (not shown) is formed at the downstream end of the fifth portion 11E, and the coolant flows out of the power conversion device B.

[0037] Here, a comparison of the power generation amount and heat resistance temperature (heat resistance) of each electronic component is as follows: The conversion modules Ba, Bb, and Bc (power supply modules) have a current value of, for example, 50 A or less, and compared to other electronic components, the bulk capacitor 16 generates a relatively small amount of heat and has a relatively low heat resistance temperature, while the switching element 15 of the conversion modules Ba, Bb, and Bc generates a relatively small amount of heat and has a relatively high heat resistance temperature.

[0038] The main inverter unit 65 (inverter) has a current of, for example, 700 A or less, and compared to other electronic components, the smoothing capacitor 67 has a relatively large amount of heat generation and a relatively low heat resistance temperature, while the switching element 66a (an electronic component, an example of a first cooling target) of the motor drive circuit 66 has a relatively large amount of heat generation and a relatively high heat resistance temperature.

[0039] The converter 70 has a current of, for example, 20 A or less, and the switching element 70a (an example of an electronic component, a second cooling target) of the converter 70 has a relatively small amount of heat generation and a relatively high heat resistance temperature compared to other electronic components. The traction motor M (particularly the stator) has a current of, for example, 700 A or less, and has a relatively large amount of heat generation and a relatively high heat resistance temperature compared to other electronic components.

[0040] In this embodiment, a bulk capacitor 16 is arranged at a position corresponding to the first portion 12A and the second portion 12B of the second cooling plate 12 (see Figure 5), and a switching element 15 of the power supply module is arranged at a position corresponding to the first portion 11A and the second portion 11B of the first cooling plate 11 (see Figure 4).

[0041] In the main inverter unit 65, a smoothing capacitor 67 is disposed at a position corresponding to the second portion 11B of the first cooling plate 11, and a switching element 66a of the motor drive circuit 66 is disposed at a position corresponding to the third portion 11C of the first cooling plate 11 (see FIG. 6). As shown in FIG. 6, the third portion 11C has a first path 11C1 and a second path 11C2 as flow paths. The third portion 11C has a plurality of pin fins 11C3 formed downward. The plurality of pin fins 11C3 are provided to generate turbulence in the coolant in the flow paths of the third portion 11C, thereby enhancing the cooling effect. The first path 11C1 is disposed below the plurality of pin fins 11C3. The second path 11C2 is disposed to the side of the plurality of pin fins 11C3 and is a flow path that communicates with the downstream side of the third portion 11C. That is, the second path 11C2 of the third portion 11C is formed between the plurality of pin fins 11C3. Therefore, in the second path 11C2 of the third portion 11C shown in FIG. 6, the coolant and the bubbles P can move from the right side toward the fourth portion 11D on the left side.

[0042] In addition, a switching element 70a of the converter 70 is arranged at a position corresponding to the fourth portion 11D of the first cooling plate 11, and a driving motor M is arranged at a position corresponding to a flow path continuing to the fifth portion 11E of the first cooling plate 11.

[0043] In this way, the cooling plates 11 and 12 have a flow path R formed therein so that the coolant flows through the bulk capacitor 16 of the second conversion module Bb (power supply module), the switching element 15 of the power supply module, the smoothing capacitor 67 of the main inverter unit 65, the switching element 66a of the inverter motor drive circuit 66, the switching element 70a of the converter 70, and the stator of the traction motor M in this order.

[0044] In this way, the power conversion device B is cooled by the coolant flowing through the first cooling plate 11 and the second cooling plate 12, and therefore does not experience an excessive temperature rise. Similarly, the inverter C is cooled by the coolant flowing through the first cooling plate 11, and therefore does not experience an excessive temperature rise.

[0045] 7, which is a comparative example, the first cooling plate 11 contains bubbles P, such as bubbles PA near the upper end 41 of the second path 11C2 of the third portion 11C and large bubbles PB near the upper end 42 of the fourth portion 11D'. In the first cooling plate 11, if the upper end 41 of the second path 11C2 of the third portion 11C is the same width (width W2) as or lower than the upper end 42 of the fourth portion 11D', such bubbles P tend to accumulate in the third portion 11C and the fourth portion 11D' and are difficult to discharge downstream. Furthermore, the accumulation of bubbles P in the third portion 11C and the fourth portion 11D' inhibits the cooling effect of the coolant, thereby reducing the cooling efficiency of the motor drive circuit 66, the converter 70, and the like in the power conversion device B.

[0046] 6, the fourth portion 11D is located above the third portion 11C and has an air bubble trapping portion 80 that allows the coolant to flow while retaining the air bubbles P. The air bubble trapping portion 80 is provided in the center of a second passage 11D2 of the fourth portion 11D, which will be described later.

[0047] Specifically, the fourth portion 11D includes a first path 11D1, a second path 11D2, and a third path 11D3 that are sequentially provided so as to surround a step portion 11G that stands upright inside the first cooling plate 11. The first path 11D1 extends upward along the step portion 11G. The second path 11D2 extends horizontally above the step portion 11G. The third path 11D3 extends downward along the step portion 11G and is connected to the fifth portion 11E.

[0048] In the first cooling plate 11, the fourth portion 11D is formed as described above, so that the upper end 41 of the second passage 11C2 of the third portion 11C is lower than the upper end 42 of the fourth portion 11D. In this embodiment, as shown in FIG. 6, there is a height difference H1 between the upper end 41 of the third portion 11C and the upper end 42 of the fourth portion 11D. Furthermore, the bubble trapping portion 80 has a coolant inlet 81 on the upstream side and a coolant outlet 82 on the downstream side. In FIG. 6, the inlet 81 and the outlet 82 have the same width W1. Furthermore, the width W3 of the first passage 11D1 is approximately the same as the width W1, and the width W4 of the flow path of the third passage 11D3 is larger than the width W1. Although not shown, the width W1 and the widths W3 to W4 may be the same width.

[0049] According to this embodiment, even if bubbles P get mixed into the coolant when the switching element 66a (first cooling target) and the switching element 70a (second cooling target) are cooled in that order by the coolant, the bubbles P can be trapped in the bubble trapping portion 80 located above the third portion 11C that cools the switching element 66a (first cooling target). Therefore, for example, by arranging the switching element 66a (first cooling target) at a position other than the position facing the bubble trapping portion 80, the switching element 66a (first cooling target) and the switching element 70a (second cooling target) can be reliably cooled by the coolant flowing through the first cooling plate 11. Furthermore, because the bubble trapping portion 80 can trap the bubbles P while allowing the coolant to flow, even if the bubbles P continue to accumulate in the bubble trapping portion 80, they do not impede the flow of the coolant.

[0050] Furthermore, in the power conversion device B of this embodiment, the switching element 70a (second cooling target) generates less heat than the switching element 66a (first cooling target). That is, in the power conversion device B, the cooling liquid flowing through the first cooling plate 11 sequentially cools the switching element 66a with a larger heat generation amount and the switching element 70a with a smaller heat generation amount, thereby effectively cooling the switching element 66a.

[0051] [Modification of the first embodiment] 8, there is a height difference H2 between the upper end 41 of the third portion 11C and the upper end 42 of the fourth portion 11D. The width W1 of the inlet 81 and the outlet 82 in the bubble trapping portion 80 is smaller than both the width W3 of the first passage 11D1 of the fourth portion 11D and the width W4 of the third passage 11D3 of the fourth portion 11D. That is, the bubble trapping portion 80 (the central portion of the second passage 11D2) is configured so that the inlet 81 and the outlet 82 of the coolant are narrower than the first passage 11D1 and the third passage 11D3, which are other portions of the fourth portion 11D. This increases the flow rate of the coolant flowing through the bubble trapping portion 80, making it easier to discharge the bubbles P from the fifth portion 11E.

[0052] Second Embodiment 9, in the second embodiment, there is a height difference H3 between the upper end 41 of the third portion 11C and the upper end 42 of the fourth portion 11D. Furthermore, in the second embodiment, the first path 11D1 of the fourth portion 11D is formed so as to slope upward toward the downstream side. In other words, the step portion 11G is sloped toward the bubble trapping portion 80. The other configurations are the same as those in the first embodiment.

[0053] Specifically, in the power converter (B), the fourth section 11D has an inclined portion (first path 11D1) that slopes upward toward the downstream side, and the bubble trapping section 80 (the center of the second path 11D2) is provided at the upper end of the inclined portion (first path 11D1). If the fourth section 11D has an inclined portion that slopes upward toward the downstream side as in this embodiment, the coolant can be smoothly guided to the bubble trapping section 80.

[0054] 9, the width W3 of the first path 11D1 is substantially the same as the width W1, and the width W4 of the flow path of the third path 11D3 is larger than the width W1. Although not shown, the width W1, the widths W3, and the widths W4 may be the same, or, as in the modified example of the first embodiment, the width W1 of the inlet 81 and the outlet 82 in the bubble trapping section 80 may be smaller than both the width W3 of the first path 11D1 of the fourth portion 11D and the width W4 of the third path 11D3 of the fourth portion 11D.

[0055] [Another embodiment] The present invention may be configured as follows in addition to the above-described embodiment (common numbers and symbols as in the embodiment are used to designate components having the same functions as in the embodiment).

[0056] (a) In the above embodiment, the cooling plates 11 and 12 are stacked one above the other, but the cooling plates may be one plate or three or more plates may be stacked.

[0057] (b) In the above embodiment, an example of a configuration was shown in which the cooling plate 11 has a flow path R formed therein so that the coolant flows to the smoothing capacitor 67 of the main inverter unit 65, the motor drive circuit 66, the converter 70, and the traction motor M. Alternatively, the cooling plate 11 may have the following configuration. The cooling plate 11 may have a flow path R formed therein so that the coolant flows to at least the motor drive circuit 66 of the main inverter unit 65 and the converter 70. In other words, it is sufficient that the cooling plates 11, 12 have a flow path R formed therein so that the coolant flows from the first object to be cooled, which has a relatively large amount of heat generation, to the second object to be cooled, which has a relatively small amount of heat generation.

[0058] (c) In the above embodiment, the coolant flow path L1 circulated the coolant through the first and second cooling plates 11 and 12 of the power conversion device B, the oil cooler 32, the water-cooled condenser 31, and the radiator 34 in this order by driving the coolant pump 33. Alternatively, the coolant flow path L1 may circulate the coolant through the first and second cooling plates 11 and 12 of the power conversion device B, the water-cooled condenser 31, the oil cooler 32, and the radiator 34 in this order by driving the coolant pump 33.

[0059] Furthermore, the configurations disclosed in the above embodiments (including other embodiments, the same applies below) can be applied in combination with configurations disclosed in other embodiments, as long as no contradictions arise. Furthermore, the embodiments disclosed in this specification are examples, and the embodiments of the present invention are not limited to these, and can be modified as appropriate within the scope that does not deviate from the purpose of the present invention.

[0060] In the above-described embodiment, the following configurations are envisioned. <1> One aspect of the power conversion device (B) includes a plurality of electronic components (66a, 70a) and a cooling plate (11, 12) through which a cooling liquid flows to cool the plurality of electronic components (66a, 70a), the plurality of electronic components (66a, 70a) including at least a first cooling target (66a) and a second cooling target (70a), the cooling plate (11, 12) including a first flow path (11C) formed in a horizontal direction to cool the first cooling target (66a), and a second flow path (11D) arranged downstream of the first flow path (11C) to cool the second cooling target (70a), the second flow path (11D) being located above the first flow path (11C) and including a bubble trapping section (80) capable of collecting bubbles (P) while allowing the cooling liquid to flow.

[0061] According to this embodiment, even if air bubbles (P) are mixed into the cooling liquid when the cooling liquid sequentially cools the first cooling target (66a) and the second cooling target (70a), the air bubbles (P) can be trapped in the air bubble trap (80) located above the first flow path (11C) that cools the first cooling target (66a). Therefore, for example, by arranging the first cooling target (66a) at a position other than the position facing the air bubble trap (80), the first cooling target (66a) and the second cooling target (70a) can be reliably cooled by the cooling liquid flowing through the cooling plate (11). Furthermore, since the air bubble trap (80) can trap the air bubbles (P) while allowing the cooling liquid to flow, even if the air bubbles (P) continue to accumulate in the air bubble trap (80) due to the slow flow velocity of the cooling liquid, the flow of the cooling liquid is not hindered.

[0062] Furthermore, by collecting the bubbles (P) in the bubble trapping section (80), it is possible to completely separate the areas in the flow path (R) where the bubbles (P) are present from the areas where the bubbles (P) are not present. Therefore, by arranging the cooling target (66a, 70a) in the area of the flow path (R) provided in the cooling plate (11, 12) where the bubbles (P) are not present, the cooling target (66a, 70a) can be effectively cooled by the coolant. Furthermore, in the bubble trapping section (80), small bubbles (P) tend to gather and form large bubbles (P), and as the bubbles (P) grow larger, the bubbles (P) tend to flow more easily with the coolant in the flow path (R). As a result, it becomes easier to discharge the bubbles (P) from the flow path (R). In this way, a power conversion device (B) capable of effectively cooling multiple electronic components (66a, 70a) has been realized.

[0063] <2> the above <1> In the power converter (B), the second flow path (11D) includes a first path (11D1) extending upward from the first flow path (11C), a second path (11D2) continuing from the first path (11D1) and extending horizontally, and a third path (11D3) extending downward from the second path (11D2), and a bubble trapping section (80) is provided in the second path (11D2).

[0064] According to the present embodiment, the second path (11D2) of the second flow path (11D) is located above the first flow path (11C), and therefore the bubbles P can be reliably stored in the bubble trapping section (80) provided in the second path (11D2).

[0065] <3> the above <1> In the power converter (B), the second flow path (11D) includes at least a first path (11D1) continuing to the first flow path (11C) and a second path (11D2) continuing to the first path (11D1), and the second path (11D2) is located above the first flow path (11C).

[0066] According to the present embodiment, the second path (11D2) of the second flow path (11D) is located above the first flow path (11C), and therefore the bubbles P can be reliably stored in the bubble trapping section (80) provided in the second path (11D2).

[0067] <4> the above <1> In the power converter (B), it is preferable that the second flow path (11D) has an inclined portion (11D1) that inclines upward toward the downstream side, and the air bubble trapping portion (80) is provided at an upper end of the inclined portion (11D1).

[0068] According to the present embodiment, the bubble trapping section (80) is provided at the upper end of the inclined portion (11D1) of the second flow path (11D), which slopes upward downstream. This allows the coolant containing the bubbles (P) to flow smoothly through the second flow path (11D) toward the bubble trapping section (80), and the bubbles (P) can be efficiently separated from the coolant and stored in the bubble trapping section (80). As a result, the first cooling target (66a) and the second cooling target (70a) can be reliably cooled by the cooling plate (11).

[0069] <5> the above <1> In the power converter (B), the bubble trapping section (80) is preferably configured so that the inlet (81) and outlet (82) of the coolant are narrower than the other portions (11D1, 11D3) of the second flow path (11D).

[0070] In this embodiment, when the inlet (81) and the outlet (82) of the cooling liquid in the bubble trapping portion (80) are configured to be narrower than the other portions (11D1, 11D3) of the second flow path (11D), the flow area of the cooling liquid at the inlet (81) and the outlet (82) is reduced, thereby increasing the flow rate of the cooling liquid. This makes it possible to actively push out the cooling liquid containing the air bubbles (P) from the bubble trapping portion (80). As a result, the air bubbles (P) are less likely to accumulate in the flow path (11C) of the cooling plate (11), and the first cooling target (66a) and the second cooling target (70a) can be reliably cooled by the cooling plate (11).

[0071] <6> the above <1> ~ <5> In any one of the power converters (B), it is preferable that the second object to be cooled (70a) generates less heat than the first object to be cooled (66a).

[0072] According to this embodiment, the first object to be cooled (66a), which generates a large amount of heat, and the second object to be cooled (70a), which generates a small amount of heat, are sequentially cooled by the cooling liquid flowing through the cooling plate (11), so that the first object to be cooled (66a) can be cooled effectively. [Industrial Applicability]

[0073] The present invention can be used in a power conversion device. [Explanation of symbols]

[0074] 11: first cooling plate (cooling plate), 11C: third section (first flow path), 11D: fourth section (second flow path), 11D1: first path (inclined section), 11D2: second path, 11D3: third path, 12: second cooling plate (cooling plate), 66: motor drive circuit, 66a: switching element (first cooling object), 70: converter, 70a: switching element (second cooling object), 80: bubble trap, 81: inlet, 82: outlet, B: power conversion device, P: bubble

Claims

1. A plurality of electronic components; a cooling plate through which a cooling liquid flows to cool the plurality of electronic components; the plurality of electronic components include at least a first cooling target and a second cooling target, the cooling plate includes a first flow path formed in a horizontal direction and cooling the first object to be cooled, and a second flow path disposed downstream of the first flow path and cooling the second object to be cooled, The second flow path is located above the first flow path and has an air bubble trapping portion that allows the cooling liquid to flow while trapping air bubbles.

2. 2. The power conversion device according to claim 1, wherein the second flow path includes a first path extending upward from the first flow path, a second path extending horizontally and continuous with the first path, and a third path extending downward from the second path, and the air bubble trapping portion is provided in the second path.

3. 2. The power conversion device according to claim 1, wherein the second flow path includes at least a first path continuous with the first flow path and a second path continuous with the first path, and the second path is located above the first flow path.

4. the second flow path has an inclined portion that inclines upward toward the downstream side, The power conversion device according to claim 1 , wherein the air bubble trapping portion is provided at an upper end of the inclined portion.

5. The power converter according to claim 1 , wherein the bubble trap portion is configured such that the inlet and outlet for the coolant are narrower than other portions of the second flow path.

6. The power conversion device according to claim 1 , wherein the second object to be cooled generates less heat than the first object to be cooled.

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