Power converter

Abstract

To provide a power conversion device that can suppress the increase in size. [Solution] The power converter 1 comprises a case 20 and a cover 30. The case 20 houses electrical components 8 that generate heat when power is supplied, and a refrigerant flow path 21 for cooling the electrical components 8 is formed therein. The cover 30 closes an opening formed along the flow direction of the refrigerant flow path 21. The cover 30 has a chamber forming section 31 that forms a chamber 33 communicating with the upstream portion of the refrigerant flow path 21, and an inlet pipe 32 provided in the chamber forming section 31 that allows refrigerant to flow into the chamber 33.

Description

Technical Field

[0001] The disclosure in this specification relates to a power conversion device.

Background Art

[0002] In a power conversion device that houses electrical components that generate heat when energized inside a case, a flow path through which a liquid refrigerant passes may be provided inside the case. In Patent Document 1, an inflow pipe and an outflow pipe of the refrigerant flow path are provided in the case and are connected to the above flow path.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] Since the case provided with the refrigerant flow path as described above is likely to increase in size, downsizing of the case is desired.

[0005] One disclosed object is to provide a power conversion device capable of suppressing an increase in size.

Means for Solving the Problems

[0006] To achieve the above object, a power conversion device according to one aspect of the present disclosure includes a case (20) that houses electrical components (8) that generate heat when energized and in which a refrigerant flow path (21) for cooling the electrical components is formed, and a cover (30) that closes an opening (24) of the refrigerant flow path. The opening is formed along the flow direction of the refrigerant flow path, and the cover has a chamber forming portion (31) that forms a chamber (33) communicating with an upstream portion of the refrigerant flow path, and an inflow pipe (32) provided in the chamber forming portion for allowing the refrigerant to flow into the chamber.

[0007] According to the disclosed power conversion device, the liquid refrigerant flowing in from the inlet pipe is temporarily stored in a chamber, diffused throughout the width of the refrigerant flow path, and then flows through the refrigerant flow path. This allows for efficient cooling of heat-generating electrical components. Furthermore, since such a chamber and inlet pipe are provided in the cover rather than the case, the overall size of the case can be kept down.

[0008] Furthermore, in order to achieve the above objective, a power converter according to another aspect of the present disclosure comprises a case (20) that houses an electrical component (8) that generates heat when energized and has a refrigerant flow path (21) formed therein for cooling the electrical component, and a cover (30) that closes an opening (24) of the refrigerant flow path, the opening being formed along the flow direction of the refrigerant flow path, and the cover having a second chamber forming section (34) that forms a second chamber (35) communicating with the downstream portion of the refrigerant flow path, and an outlet pipe (36) provided in the second chamber forming section for discharging refrigerant from the second chamber.

[0009] According to the disclosed power conversion device, the liquid refrigerant flowing from the entire width of the refrigerant flow path is collected in a chamber and then discharged through an outlet pipe. This suppresses an increase in pressure loss. Since such a chamber and outlet pipe are provided in a cover rather than a case, the overall size of the case can be kept down.

[0010] The reference numbers in parentheses above are merely examples of correspondences with specific configurations in the embodiments described later, and do not limit the technical scope in any way. [Brief explanation of the drawing]

[0011] [Figure 1] This diagram shows the circuit configuration of the power conversion device according to the first embodiment. [Figure 2] This is a plan view of the power converter according to the first embodiment with the cover attached. [Figure 3] This is a view taken along line III-III in Figure 2. [Figure 4]This is a view along the line IV-IV in Figure 2. [Figure 5] This is a plan view of the case according to the first embodiment with the cover removed. [Modes for carrying out the invention]

[0012] (First Embodiment) First, the circuit configuration of the power converter will be explained based on Figure 1.

[0013] <Circuit configuration of power converter> The power converter 1 is installed in vehicles such as electric vehicles and hybrid vehicles. The power converter 1 converts the DC voltage supplied from the DC power supply 2 installed in the vehicle into three-phase AC and outputs it to a three-phase AC motor 3 (onboard motor). The motor 3 functions as the driving source for the vehicle. The power converter 1 can also convert the power generated by the motor 3 into DC and charge the DC power supply 2. The power converter 1 is capable of bidirectional power conversion.

[0014] The power converter 1 comprises a control board 4, power cards 5 and 6, a filter capacitor 7a, a smoothing capacitor 7b, and a reactor 8. The power cards 5 and 6 are sometimes referred to as semiconductor modules, power modules, etc.

[0015] Power card 5 is a DC-DC converter that functions as a converter circuit that converts a DC voltage to a DC voltage of a different value. Power card 5 has an upper arm 5U and a lower arm 5L connected in series with each other. The upper arm 5U and lower arm 5L are composed of semiconductor elements, namely a switching element 5i and a diode 5d. The upper arm 5U and lower arm 5L together are called the upper and lower arm circuit.

[0016] The power card 6 is a DC-AC conversion unit that functions as an inverter circuit to convert the input DC power into three-phase alternating current of a predetermined frequency and output it to the motor 3. This inverter circuit also has the function of converting the AC power generated by the motor 3 into DC power. The power card 6 is provided for each of the three phases of the motor 3. The power card 6 has an upper arm 6U and a lower arm 6L that are connected in series to each other. The upper arm 6U and the lower arm 6L are composed of a switching element 6i and a diode 6d. The upper arm 6U and the lower arm 6L are collectively referred to as the upper and lower arm circuit.

[0017] In this embodiment, n-channel insulated gate bipolar transistors (IGBTs) are adopted as the switching elements 5i, 6i that constitute each arm. IGBT is an abbreviation for Insulated Gate Bipolar Transistor. The collector electrodes of the IGBTs in the upper arms 5U, 6U are connected to the high-potential power line Hi. The emitter electrodes of the IGBTs in the lower arms 5L, 6L are connected to the low-potential power line Lo. And the emitter electrodes of the IGBTs in the upper arms 5U, 6U and the collector electrodes of the IGBTs in the lower arms 5L, 6L are connected to each other.

[0018] The filter capacitor 7a is connected between the positive and negative electrodes of the DC power supply 2. The filter capacitor 7a smoothes the DC current input from the DC power supply 2.

[0019] The smoothing capacitor 7b is connected between the high-potential power line Hi and the low-potential power line Lo. The smoothing capacitor 7b is connected in parallel with the power cards 5, 6. The smoothing capacitor 7b smoothes the DC current boosted by the converter circuit of the power card 5. The smoothing capacitor 7b stores the charge of the boosted DC voltage.

[0020] The reactor 8 boosts the input voltage to the power card 5, that is, the voltage of the DC power supply 2, in accordance with the switching operation of the power card 5.

[0021] The control board 4 generates drive commands for operating the switching elements 5i and 6i of the power cards 5 and 6, and outputs them to a drive circuit section (driver) not shown in the figure. Specifically, the control board 4 outputs a PWM signal as the drive command. PWM is an abbreviation for Pulse Width Modulation. The control board 4 is configured to include, for example, a microcomputer (microcontroller).

[0022] The drive circuit section generates a drive signal based on the drive command from the control board 4 and outputs it to the gate electrodes of the corresponding switching elements 5i and 6i of the power cards 5 and 6. Thereby, the switching elements 5i and 6i are driven, that is, turned on and off. In the present embodiment, the drive circuit section is provided for each of the power cards 5 and 6.

[0023] Next, based on FIGS. 2 to 5, the structure of the power conversion device will be described. In the following description, three directions that are orthogonal to each other are defined as the X direction, the Y direction, and the Z direction. The X direction corresponds to the flow direction of the refrigerant flow path 21. The Z direction corresponds to the facing direction of the cover 30 and the case 20. The Y direction is orthogonal to both the X direction and the Z direction and corresponds to the width direction of the refrigerant flow path 21.

[0024] <Structure of the power conversion device> In addition to the components described so far, the power conversion device 1 includes a case 20 and a cover 30. The case 20 houses, for example, the electrical components of the reactor 8.

[0025] As shown in Figures 2 and 3, the case 20 has a bottom wall 26 and side walls 25. The case 20 is made of metal, for example, an aluminum-based material, and is formed by die casting. The side walls 25 are walls that constitute the outer periphery of the case 20 when viewed from the Z direction. In other words, they are walls of the case 20 that extend in the Z direction. The bottom wall 26 is a wall of the case that has a thin, flat shape in the Z direction. The bottom wall 26 has a flow path wall 22 that forms a refrigerant flow path 21. As shown in Figure 3, the flow path wall 22 has a surface 22a that forms the refrigerant flow path 21 and a back surface 22b on which electrical components such as the reactor 8 are arranged. The surface 22a and the back surface 22b are opposite surfaces to each other with respect to the Z direction.

[0026] In this embodiment, fins 23 are provided on the surface 22a, and a reactor 8 is positioned on the back surface 22b. The reactor 8 has a core, a coil wound around the core, and a resin covering the core and coil. The back surface 22b and the reactor 8 are in direct or indirect contact. The fins 23 are provided at positions that overlap with the position of the reactor 8 via the flow path wall 22. However, the fins 23 may also be located at positions that do not overlap with the reactor 8.

[0027] The shape of the fins 23 is not particularly limited, but in this embodiment, plate fins extending along the flow direction (X direction) of the refrigerant flow path 21 are used. Pin fins or corrugated fins may also be used. Alternatively, the fins 23 may be omitted. In Figures 3 to 5, some reference numerals have been omitted from the multiple fins 23. Similarly, in Figures 3 and 5, some reference numerals have been omitted from the multiple reactors 8.

[0028] The reactor 8 generates heat when power is applied. The heat emitted from the reactor 8 is transferred to the flow path wall 22 via the back surface 22b. The refrigerant flows through the refrigerant flow path 21 and exchanges heat with the surface 22a and fins 23. In other words, the refrigerant flow path 21 dissipates heat from the reactor 8. In this embodiment, a liquid refrigerant is used as the refrigerant.

[0029] In Figure 4, the Y-direction length of the portion of surface 22a where the fins are provided is greater than the Y-direction length LR of the reactor 8, but it may be the same or shorter. For more efficient cooling, it is desirable that the Y-direction length be greater than or equal to the Y-direction length LR of the reactor 8.

[0030] Figure 5 shows the state with the cover 30 removed. As shown in Figure 5, the refrigerant flow path 21 opens along its flow direction. In other words, the refrigerant flow path 21 has an opening 24 that extends parallel to the flow path wall 22. The opening 24 is formed to expose the entire refrigerant flow path 21. Therefore, all of the fins 23 formed in the refrigerant flow path 21 are also exposed from the opening 24. The shape of the refrigerant flow path 21 is such that, for example, the flow direction (X direction) of the refrigerant flow path 21 is the longitudinal direction. That is, the length of the refrigerant flow path 21 in the X direction is greater than the length in the Y direction. In this embodiment, the longitudinal direction of the fins 23 and the longitudinal direction of the refrigerant flow path 21 coincide.

[0031] On the back surface 22b, in addition to the reactor 8, a connecting component 9 that is electrically connected to the reactor 8 may be arranged. That is, the refrigerant flow path 21 may be formed so as to cool the connecting component 9 as well. This allows the connecting component 9 to be cooled as well. Of the refrigerant flow path 21, the portion that cools the connecting component 9 is designated as the extended cooling section, and the remaining portion as the normal cooling section. In this embodiment, the extended cooling section protrudes from the normal cooling section in the Y direction. The extended cooling section is not provided with fins 23. However, the extended cooling section may be provided with fins 23. Also, the refrigerant flow path 21 does not have to have an extended cooling section.

[0032] Note that the electrical components placed on the back surface 22b may be other heat-generating electrical components besides the reactor 8, such as capacitors 7a and 7b. The electrical components placed on the back surface 22b may be of one type or multiple types. It is desirable that electrical components that generate a large amount of heat be preferentially placed on the back surface 22b and cooled by the refrigerant flow path 21.

[0033] The cover 30 has a cover body 37, an inlet pipe 32, and an outlet pipe 36. The cover 30 is attached to the bottom wall 26 such that the cover body 37 closes the opening 24 of the refrigerant flow path 21. In other words, the bottom wall 26 and the cover body 37 are facing each other. A sealing material 40, for example, is placed between the cover 30 and the bottom wall 26. The sealing material 40 is attached to the bottom wall 26 so as to encircle the refrigerant flow path 21 and prevents refrigerant from leaking between the bottom wall 26 and the cover 30.

[0034] In this embodiment, the cover 30 is fixed to the bottom wall 26 with a plurality of bolts 50. The bolts 50 are also arranged to surround the refrigerant flow path 21, and holes are provided in the sealing material 40 for the bolts to pass through. In other words, the bolts 50 are fixed to the bottom wall 26 by passing through the sealing material 40.

[0035] The cover body 37 has a first chamber forming portion 31 and a second chamber forming portion 34. The first chamber forming portion 31 is provided at one end of the cover body 37 in the X direction and forms the first chamber 33. The first chamber forming portion 31 protrudes in the Z direction, that is, in the direction opposite to the refrigerant flow path 21 (Z direction), on the side opposite to the refrigerant flow path 21.

[0036] The inlet pipe 32 is formed in the first chamber forming section 31 and is connected to a refrigerant pipe extending from a circulation device (not shown). The refrigerant flows from the circulation device into the first chamber 33 via the inlet pipe 32. The first chamber 33 communicates with the refrigerant flow path 21 at the first communication surface 33a (communication surface). Therefore, the refrigerant that flows into the first chamber 33 flows into the refrigerant flow path 21.

[0037] The second chamber forming section 34 is provided at the other end of the cover body 37 in the X direction and forms the second chamber 35. The second chamber forming section 34 also protrudes in the Z direction, similar to the first chamber forming section. The outflow pipe 36 is formed in the second chamber forming section 34 and is connected to a refrigerant pipe extending from a circulation device (not shown). The second chamber 35 is in communication with the refrigerant flow path 21 at the second communication surface 35a. Therefore, the refrigerant that has passed through the refrigerant flow path 21 flows out into the second chamber 35 and returns to the circulation path via the outflow pipe 36.

[0038] From the above, it can be said that the first chamber 33 communicates with the upstream portion of the refrigerant flow path 21, and the second chamber 35 communicates with the downstream portion of the refrigerant flow path 21. In other words, the first communication surface 33a is located in the upstream portion of the refrigerant flow path, and the second communication surface 35a is located in the downstream portion of the refrigerant flow path 21. The first communication surface 33a and the second communication surface 35a are surfaces that extend in the XY plane.

[0039] The inlet pipe 32 and outlet pipe 36 are formed to allow the refrigerant to flow in and out in the same direction as the flow direction (X direction) of the refrigerant flow path 21. In other words, the inlet pipe 32 has a shape that extends in the X direction and is formed on the opposite side of the first chamber forming section 31 from the second chamber forming section 34. The outlet pipe 36 also has a shape that extends in the X direction and is formed on the opposite side of the second chamber forming section 34 from the first chamber forming section 31.

[0040] In this embodiment, the inlet pipe 32 and outlet pipe 36 are straight, but they may be curved. If they are curved, the portion of the inlet pipe 32 closest to the connection with the first chamber forming portion 31 has the structure described above. Similarly, the portion of the outlet pipe 36 closest to the connection with the second chamber forming portion 34 has the structure described above.

[0041] The Y-direction length LC of the first chamber 33 and the Y-direction length of the second chamber are greater than the inner diameters of the inlet pipe 32 and the outlet pipe 36. As a result, the first chamber 33 distributes the refrigerant flowing in from the inlet pipe 32 across the entire width direction (Y direction) of the refrigerant flow path 21. The second chamber 35 collects the refrigerant flowing from the entire width direction (Y direction) of the refrigerant flow path 21 and discharges it into the outlet pipe 36. To effectively perform the above functions, it is desirable that the Y-direction length LC of the first chamber 33 and the Y-direction length of the second chamber be approximately the same as the Y-direction length of the refrigerant flow path 21.

[0042] Furthermore, as shown in Figure 4, the Y-direction length LC of the first chamber 33 is greater than the Y-direction length LR of the reactor 8. Similarly, the Y-direction length of the second chamber 35 is also greater than the Y-direction length LR of the reactor 8. Note that the Y-direction lengths LC of the first chamber 33 and the Y-direction length of the second chamber 35 may be less than or equal to the Y-direction length LR of the reactor 8. However, for efficient cooling, it is desirable that they be greater than or equal to the Y-direction length LR of the reactor 8.

[0043] Fins 23 are provided in the refrigerant flow path 21 at a position facing the first chamber 33. In other words, fins 23 are present in the flow path wall 22 at a position facing the first communication surface 33a. Similarly, fins 23 are also provided at a position facing the second chamber 35. In this embodiment, the Y-direction length of the portion where the fins 23 are provided is approximately the same as the Y-direction length LC of the first chamber 33, but it may be significantly different.

[0044] The first chamber forming section 31 and the second chamber forming section 34 are located inward from the outer circumference of the case 20 when viewed in the Z direction, that is, from the direction in which the case 20 and the cover 30 face each other. In other words, the distance between the first chamber forming section 31 and the second chamber forming section is smaller than the distance between the opposing side walls 25 in the X direction. In other words, the distance between the first chamber forming section 31 and the second chamber forming section 34 is shorter than the length of the bottom wall 26 in the X direction. Also, the lengths of the first chamber forming section 31 and the second chamber forming section in the Y direction are smaller than the length of the bottom wall 26 in the Y direction.

[0045] In Figure 1, the tip of the inlet pipe 32 appears to protrude outward in the X direction beyond the side wall 25, but it does not have to protrude. The tip of the inlet pipe 32 refers to the portion of the inlet pipe 32 that is connected to the refrigerant pipe extending from a circulation device (not shown). In other words, the entire inlet pipe 32 may be located inside the outer circumference of the case 20 when viewed from the Z direction.

[0046] In this embodiment, the first chamber forming portion 31 and the second chamber forming portion 34 are provided at the X-direction ends of the cover body 37, but they do not have to be at the ends. That is, they may be located closer to the center of the cover body 37. However, it is desirable that the X-direction position of the upstream end of the first communication surface 33a is approximately the same as the X-direction position of the upstream end of the refrigerant flow path 21. Similarly, it is desirable that the X-direction position of the downstream end of the second communication surface 35a is approximately the same as the X-direction position of the downstream end of the refrigerant flow path 21.

[0047] The first chamber 33 has a slope with respect to the XY plane such that the length (height) in the Z direction gradually decreases from upstream to downstream of the first communication surface 33a. The second chamber 35 has a slope with respect to the XY plane such that the length in the Z direction gradually increases from upstream to downstream of the second communication surface 35a. In other words, the first chamber 33 has a slope with respect to the XY plane such that the length in the Z direction gradually decreases as it moves away from the connection point with the inlet pipe 32 in the X direction. The second chamber 35 has a slope with respect to the XY plane such that the length in the Z direction gradually decreases as it moves away from the connection point with the outlet pipe 36 in the X direction.

[0048] In this embodiment, the gradient is constant, but it may change continuously. That is, the shape of the slope formed by the first chamber 33 and the second chamber 35 when viewed from the Y direction may be straight, or it may be, for example, an arc.

[0049] Furthermore, the first chamber 33 may have a portion where the Z-direction length gradually increases from upstream to downstream of the first communication surface 33a, or a portion where the Z-direction length does not change. For example, the Z-direction length of the first chamber 33 may gradually increase from upstream to downstream of the first communication surface 33a, then become constant, and then gradually decrease. Similarly, the second chamber 35 may have a portion where the Z-direction length gradually decreases from upstream to downstream of the second communication surface 35a, or a portion where the Z-direction length does not change.

[0050] A gentler gradient suppresses fluid separation, thereby reducing pressure loss and improving fluidity. However, a gentler gradient increases the X-direction length of the first chamber 33 and the second chamber. This increases the flow path cross-sectional area, which tends to decrease the flow velocity. In this embodiment, the X-direction position of the upstream end of the first communication surface 33a is the same as the X-direction end of the reactor 8. Furthermore, in the X-direction, more than half of the reactor 8 overlaps with the first communication surface 33a via the flow path wall 22.

[0051] <Effects and Effects in the First Embodiment> According to the power converter 1 of this embodiment, the case 20 is provided with a refrigerant flow path 21 for cooling electrical components such as a reactor 8. The cover 30 that closes the opening 24 of the refrigerant flow path 21 has the following structure. Specifically, the cover 30 has a first chamber forming section 31 that forms a first chamber 33 communicating with the upstream portion of the refrigerant flow path 21, and an inlet pipe 32 provided in the first chamber forming section 31 for introducing refrigerant into the first chamber 33.

[0052] This allows the refrigerant flowing in from the inlet pipe 32 to be temporarily stored in the first chamber 33, diffused throughout the width direction (Y direction) of the refrigerant flow path 21, and then flow into the refrigerant flow path 21. Therefore, heat-generating electrical components such as the reactor 8 can be efficiently cooled. Furthermore, since the first chamber 33 and the inlet pipe 32 are provided in the cover rather than the case 20, the size of the case 20 can be kept down.

[0053] Furthermore, in this embodiment, in addition to the first chamber 33, there is also a second chamber 35. As a result, the refrigerant flowing from the entire width direction (Y direction) of the refrigerant flow path 21 is collected in the second chamber 35 and then discharged from the outlet pipe 36. Therefore, an increase in pressure loss can be suppressed. Since the second chamber 35 and outlet pipe 36 are provided in the cover 30 rather than the case 20, the effect of suppressing the enlargement of the case 20 as described above can be more effectively achieved.

[0054] Furthermore, in this embodiment, the first chamber forming portion 31 is located inside the outer circumference of the case 20 when viewed from the Z direction. Therefore, as described above, it is possible to efficiently cool heat-generating electrical components such as the reactor 8 while suppressing an increase in the size of the power conversion device 1 in the direction perpendicular to the Z direction.

[0055] Furthermore, in this embodiment, the second chamber forming section 34 is also located inward from the outer circumference of the case 20 when viewed from the Z direction. Therefore, similar to the first chamber forming section 31, it is possible to suppress the enlargement of the power conversion device 1 in the direction perpendicular to the Z direction.

[0056] Furthermore, in this embodiment, the inlet pipe 32 has a shape that extends in a direction perpendicular to the Z direction. More specifically, the inlet pipe 32 has a shape that extends in the X direction. Therefore, it is possible to suppress the increase in size of the power converter 1 in the Z direction.

[0057] Furthermore, in this embodiment, the outflow pipe 36 also extends in a direction perpendicular to the Z direction. More specifically, the outflow pipe 36 extends in the X direction. Therefore, it is possible to suppress the increase in size of the power converter 1 in the Z direction.

[0058] Furthermore, in this embodiment, the Y-direction length LC of the first chamber 33 is greater than or equal to the Y-direction length LR of the reactor 8. This allows the first chamber 33 to diffuse the coolant throughout the entire Y-direction of the reactor 8. Therefore, the cooling efficiency improvement effect of the first chamber 33 described above can be more fully realized.

[0059] Furthermore, in this embodiment, the Y-direction length of the second chamber 35 is greater than or equal to the Y-direction length LR of the reactor 8. As a result, the refrigerant flowing from the entire width direction (Y-direction) of the refrigerant flow path 21 flows through the entire Y-direction of the reactor 8 before being concentrated in the second chamber 35. Therefore, as described above, the effect of improving cooling efficiency can be further demonstrated.

[0060] Furthermore, in this embodiment, the case 20 has a flow path wall 22 that forms a refrigerant flow path 21. Fins 23 that exchange heat with the refrigerant are provided on the surface 22a of the flow path wall 22, and heat-generating electrical components such as the reactor 8 are in contact with the back surface 22b of the flow path wall 22. At least a portion of the fins 23 is positioned to overlap with the reactor 8 via the flow path wall 22. This allows the reactor 8 to be cooled efficiently.

[0061] Furthermore, in this embodiment, at least a portion of the fins 23 arranged in the refrigerant flow path 21 is positioned opposite the first chamber 33. Here, if the first chamber 33 is provided in the case 20 contrary to this disclosure, that is, if the upstream end of the refrigerant flow path functions as the first chamber 33, the aforementioned diffusion function will be exerted in the upstream portion. In other words, it is not possible to provide fins 23 in that upstream portion. In contrast, according to the structure of this disclosure, by providing the first chamber 33 in the cover 30, it becomes possible to arrange fins 23 in the portion of the refrigerant flow path 21 that faces the first chamber 33 (the upstream portion). In other words, the range in the refrigerant flow path 21 over which fins 23 can be arranged can be expanded. Therefore, cooling performance can be improved.

[0062] Furthermore, in this embodiment, at least a portion of the fins 23 are positioned facing the second chamber 35. This structure also expands the range in the refrigerant flow path 21 over which the fins 23 can be placed. Thus, cooling efficiency can be improved.

[0063] Furthermore, according to the structure of this disclosure, the first chamber 33 has a gradient such that the length in the Z direction gradually decreases from upstream to downstream of the first communication surface 33a that communicates with the refrigerant flow path 21. In other words, the cross-sectional area of ​​the first chamber 33 gradually decreases. Therefore, the flow velocity of the refrigerant flowing from the first chamber 33 into the refrigerant flow path 21 can be increased, thereby improving the heat transfer coefficient of the refrigerant in the refrigerant flow path 21 and improving the cooling efficiency. Moreover, when narrowing the cross-sectional area of ​​the first chamber 33 to increase the flow velocity, the gradient helps to suppress an increase in pressure loss.

[0064] Furthermore, according to this embodiment, the second chamber 35 has a gradient such that the length in the Z direction gradually increases from upstream to downstream of the second communication surface 35a that communicates with the refrigerant flow path 21. This makes it possible to suppress an increase in pressure loss.

[0065] (Other embodiments) The disclosure in this specification is not limited to the exemplary embodiments. The disclosure encompasses the exemplary embodiments and variations thereof by those skilled in the art. For example, the disclosure is not limited to the combinations of parts and elements shown in the embodiments, but can be implemented in various variations. The disclosure can be implemented in a variety of combinations. The disclosure may have additional parts that can be added to the embodiments. The disclosure encompasses embodiments in which parts and elements have been omitted. The disclosure encompasses substitutions or combinations of parts and elements between one embodiment and another. The scope of the disclosed technical field is not limited to the descriptions of the embodiments. The scope of the disclosed technical field is indicated by the claims and should be understood to include all modifications within the meaning and scope equivalent to the claims.

[0066] Spatially relative terms such as "inside," "outside," "back," "below," "low," "above," and "high" are used here to facilitate descriptions of the relationship between one element or feature and other elements or features, as illustrated. Spatially relative terms may be intended to encompass different orientations of the device in use or operation, in addition to the orientation depicted in the drawings. For example, if the device in the drawing is turned upside down, an element described as "below" or "directly below" another element or feature will be oriented "above" the other element or feature. Thus, the term "below" can encompass both up and down orientations. The device may also be oriented in other directions (it may be rotated 90 degrees or in other directions), and the spatially relative descriptors used in this specification will be interpreted accordingly.

[0067] In the first embodiment described above, both the inlet pipe 32 and the outlet pipe 36 are provided in the cover 30, but either one may be provided in the case 20. For example, the inlet pipe 32 may be provided in the cover 30 and the outlet pipe 36 may be provided in the case. In this case, as in the first embodiment, the first chamber forming section 31 is provided in the cover 30. On the other hand, the second chamber forming section 34 is not formed, and the case 20 is given the function of a chamber. That is, the refrigerant flowing from the entire Y direction of the refrigerant flow path 21 is collected in the downstream section and flows out into the outlet pipe 36. In this case, the fins 23 are not provided in the downstream section of the refrigerant flow path 21.

[0068] In the first embodiment described above, the inlet pipe 32 is provided at one end of the cover 30 in the X direction, and the outlet pipe 36 is provided at the other end. However, the inlet pipe 32 and the outlet pipe 36 may be provided at one end in the X direction so that they are aligned in the Y direction. In this case, the first chamber forming section 31 and the second chamber forming section 34 are also provided at one end in the X direction so that they are aligned in the Y direction. A partition plate extending in the X direction is provided in the refrigerant flow path 21 so as to separate the upstream side and the downstream side. The partition plate is provided so as to have an opening at the other end of the refrigerant flow path 21 in the X direction for the refrigerant to pass through. In other words, the refrigerant may flow through the refrigerant flow path 21 in a U-shape.

[0069] In the first embodiment described above, the inlet pipe 32 is formed to allow refrigerant to flow into the first chamber 33 in the same direction as the flow direction, but it may also be formed to allow refrigerant to flow in the opposite direction to the flow direction. That is, the inlet pipe may have a shape that extends in the X direction, and the inlet pipe 32 may be provided on the same side of the first chamber forming portion as the second chamber forming portion 34. In this case, the first chamber 33 has a slope such that the height in the Z direction gradually decreases as it moves away from the connection portion with the inlet pipe 32 in the X direction.

[0070] Furthermore, the inlet pipe 32 may have a shape that extends in the Y direction or in the Z direction. Accordingly, the connection portion between the inlet pipe 32 and the first chamber forming portion may be changed. For example, in the case of a shape that extends in the Y direction, the inlet pipe 32 is provided at one end of the first chamber forming portion 31 in the Y direction. In this case, the first chamber 33 has a slope such that the height in the Z direction gradually decreases as it moves away from the connection portion with the inlet pipe 32 in the Y direction.

[0071] The same structure applies to the outflow pipe 36. That is, the outflow pipe 36 may have a shape that extends in the X direction and may be provided on the same side of the second chamber forming section 34 as the first chamber forming section 31. The outflow pipe 36 may also have a shape that extends in the Y direction or in the Z direction.

[0072] In the first embodiment described above, the first chamber forming portion 31 and the second chamber forming portion 34 are located inside the outer circumference of the case 20 when viewed from the Z direction, but they may protrude outwards.

[0073] In the first embodiment described above, fins 23 are located in the refrigerant flow path 21 at positions facing the first chamber 33 and at positions facing the second chamber 35. However, fins 23 may not be present at these positions. Alternatively, fins 23 may be present at positions facing either the first chamber 33 or the second chamber 35.

[0074] In the first embodiment described above, the first chamber 33 has a slope such that the length in the Z direction gradually decreases from upstream to downstream of the first communication surface 33a. Similarly, the second chamber 35 has a slope such that the length in the Z direction gradually increases from upstream to downstream of the second communication surface 35a. However, the above slopes are not required. For example, the height in the Z direction of the first chamber 33 may be constant from upstream to downstream of the first communication surface 33a.

[0075] (Disclosure of technical ideas) This specification discloses several technical concepts, as listed in the following paragraphs. Some paragraphs are written in a multiple dependent form, where subsequent paragraphs optionally refer to preceding paragraphs. Furthermore, some paragraphs are written in a multiple dependent form, referring to other multiple dependent forms. These paragraphs written in multiple dependent forms define several technical concepts.

[0076] (Technical thought 1) A case (20) that houses an electrical component (8) that generates heat when power is applied, and has a refrigerant flow path (21) formed in it for cooling the electrical component, The system includes a cover (30) that closes the opening (24) of the refrigerant flow path, The opening is formed along the flow direction of the refrigerant flow path, The aforementioned cover is A chamber forming section (31) that forms a chamber (33) communicating with the upstream portion of the refrigerant flow path, A power conversion device having an inlet pipe (32) provided in the chamber forming section for introducing a refrigerant into the chamber.

[0077] (Technical thought 2) The power conversion device according to technical concept 1, wherein the chamber forming portion is located inside the outer circumference of the case when viewed from the opposite direction of the cover and the refrigerant flow path.

[0078] (Technical Thought 3) The power conversion device according to technical concept 1 or 2, wherein the inlet pipe extends in a direction perpendicular to the opposing direction of the cover and the refrigerant flow path.

[0079] (Technical Thought 4) The width direction is defined as the direction perpendicular to the opposing direction of the cover and the refrigerant flow path, and also perpendicular to the flow direction. The power conversion device according to any one of technical ideas 1 to 3, wherein the length of the chamber in the width direction (LC) is greater than or equal to the length of the electrical component in the width direction (LR).

[0080] (Technical Thought 5) The case has a flow path wall (22) that forms the refrigerant flow path, The surface (22a) of the flow path wall that forms the refrigerant flow path is provided with fins (23) that exchange heat with the refrigerant. The electrical component is in contact with the back surface (22b) of the flow channel wall. A power conversion device according to any one of technical ideas 1 to 4, wherein at least a portion of the fins is positioned to overlap with the electrical components through the flow path wall.

[0081] (Technical Thought 6) The refrigerant flow path is equipped with fins (23) that exchange heat with the refrigerant, A power conversion device according to any one of technical ideas 1 to 5, wherein at least a portion of the fins is located opposite the chamber.

[0082] (Technical Thought 7) The inlet pipe is formed to allow the refrigerant to flow into the chamber in the same direction as the flow direction. The power conversion device according to any one of technical concepts 1 to 6, wherein the chamber has a gradient such that the length of the surface (33a) communicating with the refrigerant flow path gradually decreases from upstream to downstream, in the direction opposite to the cover and the refrigerant flow path.

[0083] (Technical Thought 8) The aforementioned chamber is designated as the first chamber, and the chamber forming section is designated as the first chamber forming section. The aforementioned cover is A second chamber forming section (34) that forms a second chamber (35) communicating with the downstream portion of the refrigerant flow path, A power conversion device according to any one of technical ideas 1 to 7, comprising an outlet pipe (36) provided in the second chamber forming section for discharging a refrigerant from the second chamber.

[0084] (Technical Thought 9) A case (20) that houses an electrical component (8) that generates heat when power is applied, and has a refrigerant flow path (21) formed in it for cooling the electrical component, The system includes a cover (30) that closes the opening (24) of the refrigerant flow path, The opening is formed along the flow direction of the refrigerant flow path, The aforementioned cover is A second chamber forming section (34) that forms a second chamber (35) communicating with the downstream portion of the refrigerant flow path, A power conversion device having an outlet pipe (36) provided in the second chamber forming section for discharging refrigerant from the second chamber. [Explanation of symbols]

[0085] 8...Electrical component (reactor), 20...Case, 21...Refrigerant flow path, 22...Flow path wall, 22a...Front surface, 22b...Back surface, 23...Fin, 24...Opening, 30...Cover, 31...First chamber forming section (chamber forming section), 32...Inlet pipe, 33...First chamber (chamber), 33a...First communication surface (communication surface), 34...Second chamber forming section, 35...Second chamber, 36...Outlet pipe, LR...Width of the reactor, LC...Width of the first chamber.

Claims

1. A case (20) that houses an electrical component (8) that generates heat when power is applied, and has a refrigerant flow path (21) formed in it for cooling the electrical component, The device comprises a cover (30) that closes the opening (24) of the refrigerant flow path, The opening is formed along the flow direction of the refrigerant flow path, The aforementioned cover is A chamber forming section (31) that forms a chamber (33) communicating with the upstream portion of the refrigerant flow path, A power conversion device having an inlet pipe (32) provided in the chamber forming section for introducing a refrigerant into the chamber.

2. The power conversion device according to claim 1, wherein the chamber forming portion is located inside the outer circumference of the case when viewed from the opposite direction of the cover and the refrigerant flow path.

3. The power conversion device according to claim 1 or 2, wherein the inlet pipe extends in a direction perpendicular to the opposing direction of the cover and the refrigerant flow path.

4. The width direction is defined as the direction perpendicular to the opposing direction of the cover and the refrigerant flow path, and also perpendicular to the flow direction. The power conversion device according to claim 1 or 2, wherein the widthwise length (LC) of the chamber is greater than or equal to the widthwise length (LR) of the electrical component.

5. The case has a flow path wall (22) that forms the refrigerant flow path, The surface (22a) of the flow path wall that forms the refrigerant flow path is provided with fins (23) that exchange heat with the refrigerant. The electrical component is in contact with the back surface (22b) of the flow channel wall. The power conversion device according to claim 1 or 2, wherein at least a portion of the fins is positioned to overlap with the electrical components through the flow path wall.

6. The refrigerant flow path is equipped with fins (23) that exchange heat with the refrigerant, The power conversion device according to claim 1 or 2, wherein at least a portion of the fins is located opposite the chamber.

7. The inlet pipe is formed to allow the refrigerant to flow into the chamber in the same direction as the flow direction. The power conversion device according to claim 1 or 2, wherein the chamber has a gradient such that the length of the surface (33a) communicating with the refrigerant flow path gradually decreases from upstream to downstream, in the direction opposite to the cover and the refrigerant flow path.

8. The aforementioned chamber is designated as the first chamber, and the chamber forming section is designated as the first chamber forming section. The aforementioned cover is A second chamber forming section (34) that forms a second chamber (35) communicating with the downstream portion of the refrigerant flow path, The power conversion device according to claim 1 or 2, further comprising an outlet pipe (36) provided in the second chamber forming section for discharging refrigerant from the second chamber.

9. A case (20) that houses an electrical component (8) that generates heat when power is applied, and has a refrigerant flow path (21) formed in it for cooling the electrical component, The device comprises a cover (30) that closes the opening (24) of the refrigerant flow path, The opening is formed along the flow direction of the refrigerant flow path, The aforementioned cover is A second chamber forming section (34) that forms a second chamber (35) communicating with the downstream portion of the refrigerant flow path, A power conversion device having an outlet pipe (36) provided in the second chamber forming section for discharging refrigerant from the second chamber.

Images