Power conversion apparatus

Abstract

The embodiments of the present application relate to the technical field of power electronics. Provided is a power conversion apparatus. The power conversion apparatus comprises a housing, a circuit board, a radiator and a first heat exchanger, wherein a power cavity is formed in the housing, a heat dissipation cavity is formed outside the housing, the housing comprises a partition plate located between the power cavity and the heat dissipation cavity, an opening is provided in the partition plate, the circuit board is arranged in the power cavity, and the side of the circuit board that faces the opening is provided with a first power device; the radiator is arranged in the heat dissipation cavity and comprises a first base plate and a first heat dissipation portion, wherein the first base plate is arranged at the opening and is in contact with the first power device, a first gas-liquid channel is provided in the first base plate, a second gas-liquid channel in communication with the first gas-liquid channel is provided in the first heat dissipation portion, and a cooling working medium for gas-liquid conversion is provided in the first gas-liquid channel; and the first heat exchanger is located in the power cavity or the heat dissipation cavity. By means of the above technical solution, targeted heat dissipation can be performed on a device suffering from severe heat generation in the power conversion apparatus, such that the power conversion apparatus operates stably.

Description

Power conversion equipment

[0001] This application claims priority to Chinese patent application No. 202410564999.6, filed with the State Intellectual Property Office of China on April 30, 2024, entitled "Power Conversion Device", the entire contents of which are incorporated herein by reference. Technical Field

[0002] This application relates to the field of power electronics technology, and in particular to a power conversion device. Background Technology

[0003] An inverter is a power conversion device that converts direct current (DC) to alternating current (AC). Inverters and other power conversion devices generate significant heat during operation. With technological advancements, the demand for heat dissipation in inverters and other power conversion devices has increased dramatically.

[0004] In related technologies, heat dissipation is achieved through overall heat dissipation of the entire power conversion device. However, power conversion devices include multiple high-power components, such as high-power chips. These components generate significant heat, and the heat dissipation methods used in these technologies cannot provide precise cooling for them, thus affecting the operational stability of the power conversion device. Summary of the Invention

[0005] This application provides a power conversion device that can perform targeted heat dissipation on components that generate significant heat in the power conversion device, thereby enabling the power conversion device to operate stably.

[0006] To achieve the above objectives, this application adopts the following technical solution:

[0007] This application provides a power conversion device, which includes a housing, a circuit board, a heat sink, and a first heat exchanger. A sealed power cavity is formed inside the housing, and an open, ventilated heat dissipation cavity is formed outside the housing. The housing includes a partition between the power cavity and the heat dissipation cavity. The power cavity has a higher protection level than the heat dissipation cavity. An opening is provided on the partition. The circuit board is disposed inside the power cavity, and a first power device is mounted on the side of the circuit board facing the opening. The first power device constitutes the power conversion circuit of the power conversion device to convert the DC power input to the power conversion device. The heat sink is disposed inside the heat dissipation cavity and includes a first substrate and a first heat dissipation section. The circuit board is positioned at the opening and in thermal contact with the first power device inside the power cavity. The first heat dissipation part extends outward from the first substrate. The first substrate has a first gas-liquid channel, and the first heat dissipation part has a second gas-liquid channel communicating with the first gas-liquid channel. The first gas-liquid channel contains a cooling medium for gas-liquid conversion. The angle between the first gas-liquid channel and the second gas-liquid channel is 90 degrees or greater than 90 degrees and less than 180 degrees. Electronic devices are mounted on the side of the circuit board opposite to where the first power device is mounted. The first heat exchanger is located inside the power cavity or heat dissipation cavity and is used to transfer heat from the power cavity to the heat dissipation cavity to cool the electronic devices.

[0008] When the first power device in the power conversion equipment generates significant heat, the heat is transferred to the first substrate, heating the cooling medium within the substrate. As the liquid cooling medium in the first gas-liquid channel heats up, at least a portion of it becomes gaseous. This gaseous cooling medium flows (rises) into the second gas-liquid channel of the first heat dissipation section. The open, ventilated heat dissipation cavity facilitates heat exchange between the cooling medium in the first heat dissipation section and the outside environment, causing the gaseous cooling medium to rapidly dissipate heat and condense within the first heat dissipation section, gradually returning to a liquid state before flowing back into the first substrate. This cycle continuously dissipates heat from the first power device. This application achieves stable operation of the power conversion equipment by providing targeted heat dissipation to the device generating significant heat (e.g., the first power device). The specific angle between the first and second gas-liquid channels ensures that, under gravity, the cooling medium can smoothly flow back to the position in the first substrate near the thermally conductive contact with the first power device.

[0009] Furthermore, the power cavity is sealed and has a higher protection level than the heat dissipation cavity, reducing the possibility of external impurities entering the power cavity. Additionally, the first substrate is positioned at the opening, allowing it to contact the first power device while also shielding the opening, further reducing the possibility of mutual interference between the heat dissipation cavity and the power cavity. This allows the circuit board to be placed within a relatively well-protected cavity, ensuring the safety of other components while simultaneously dissipating heat from the heat-generating device, thus reducing the risk of power conversion equipment failure.

[0010] Furthermore, the circuit board is located inside the power cavity. When the power conversion device is running, the circuit board and the electronic components on it generate a lot of heat, making the temperature inside the power cavity high. The first heat exchanger allows the hot air inside the power cavity to exchange heat with the cold air inside the heat dissipation cavity, reducing the temperature inside the power cavity and enabling the power conversion device to operate stably.

[0011] In one optional embodiment, the first substrate extends vertically and protrudes from the first heat dissipation portion, and the first power device makes thermally conductive contact with the portion of the first substrate protruding from the first heat dissipation portion.

[0012] By adopting the above design method, the overlap area between the first heat dissipation part and the first power device can be reduced, and the first heat dissipation part will have more area to exchange heat with the air in the heat dissipation cavity. This reduces the impact of the heat from the first power device on the condensation of the cooling medium in the first heat dissipation part, allowing the cooling medium to condense quickly in the first heat dissipation part, which is beneficial to improving the heat dissipation effect of the heat sink.

[0013] In one optional embodiment, the first heat exchanger is located inside the power cavity, and a first heat exchange channel is formed inside the first heat exchanger. The first heat exchange channel is isolated from the power cavity and has an inlet and an outlet disposed on the first heat exchanger. Both the inlet and outlet of the first heat exchange channel are connected to the heat dissipation cavity.

[0014] Air in the heat dissipation cavity can enter the first heat exchange channel and then exchange heat with the hot air in the power cavity through the first heat exchanger. The heat dissipation cavity is open for ventilation, so that outside air can continuously enter the first heat exchange channel, reducing the temperature in the power cavity and enabling the power conversion equipment to operate stably.

[0015] In one optional embodiment, the first heat exchanger is located inside the heat dissipation cavity, and a first heat exchange channel is formed inside the first heat exchanger. The first heat exchange channel is isolated from the heat dissipation cavity. The first heat exchange channel has an inlet and an outlet disposed on the first heat exchanger, and both the inlet and outlet of the first heat exchange channel are connected to the power cavity.

[0016] The first heat exchanger allows hot air from the power cavity to enter the first heat exchange channel, where it exchanges heat with the air in the heat dissipation cavity. By designing the heat dissipation cavity as an open, ventilated structure, sufficient heat exchange between the air in the first heat exchange channel and the surrounding cool air is achieved, lowering the temperature within the power cavity and enabling stable operation of the power conversion equipment. Furthermore, placing the first heat exchanger within the heat dissipation cavity improves heat dissipation efficiency and accelerates the heat dissipation rate.

[0017] In one alternative embodiment, the first substrate extends vertically and protrudes from the first heat dissipation portion, and the first heat exchanger crosses the first substrate and overlaps with the portion of the first substrate protruding from the first heat dissipation portion.

[0018] In order to ensure that the first power device is at least partially located below the first heat dissipation part, the first substrate extends downward and forms a space with the first heat dissipation part, and the first heat exchanger is installed in this space. That is, the first heat exchanger is installed below the first heat dissipation part and overlaps with the part of the first substrate that protrudes from the first heat dissipation part. This allows the heat dissipation radiator and the first heat exchanger to be installed more compactly and reduces the space occupied by the heat dissipation cavity.

[0019] In one optional embodiment, the first heat exchanger is located inside the heat dissipation cavity. The first heat exchanger includes a heat-conducting plate and heat dissipation fins connected to each other. The heat-conducting plate is thermally bonded to the first substrate. A first fan is provided inside the heat dissipation cavity to generate airflow through the heat dissipation fins.

[0020] As the temperature of the electronic components rises, the temperature of the power cavity also rises. The heat inside the power cavity is transferred to the heat-conducting plate through the first substrate, and then the heat-conducting plate transfers the heat to the heat sink fins. The first fan blows air towards the heat sink fins, and the heat sink cavity is open for ventilation, which allows the heat on the heat sink fins to be blown out of the heat sink cavity, that is, blown to the outside. As the first fan rotates continuously, it can continuously dissipate heat from the heat sink fins, which indirectly dissipates heat from the electronic components in the power cavity.

[0021] In one optional embodiment, the first substrate extends vertically and protrudes from the first heat dissipation portion, a heat-conducting plate is thermally bonded to the portion of the first substrate protruding from the first heat dissipation portion, and heat dissipation fins are located below the first heat dissipation portion.

[0022] The first substrate extends downwards and forms a space with the first heat dissipation part. The first heat exchanger is installed within this space, allowing for a more compact installation of the heat sink and the first heat exchanger, reducing the space occupied by the heat dissipation cavity. Furthermore, the first power device contacts the protruding portion of the first substrate, and the heat-conducting plate also contacts the protruding portion of the first substrate. Combined with the heat dissipation fins, this further improves heat dissipation for the first power device.

[0023] In one optional embodiment, a through-hole is provided on the partition plate, and the first heat exchanger includes a heat-conducting plate and multiple heat dissipation fins, the multiple heat dissipation fins including a first heat dissipation fin and a second heat dissipation fin. The heat-conducting plate is disposed at the through-hole, and the first heat dissipation fin and the second heat dissipation fin are respectively fixed to different surfaces of the heat-conducting plate; the heat-conducting plate and the first heat dissipation fin are located in the heat dissipation cavity, and the second heat dissipation fin extends into the power cavity through the through-hole; or, the heat-conducting plate and the second heat dissipation fin are located in the power cavity, and the first heat dissipation fin extends into the heat dissipation cavity through the through-hole; a second fan is provided in the power cavity to generate airflow through the second heat dissipation fin.

[0024] The temperature of the electronic device increases, causing the power cavity temperature to rise. The second fan blows air onto the second heat sink fins, allowing heat from the power cavity to be conducted to them. The heat from the power cavity is then transferred through the second heat sink fins to the heat dissipation plate, and from there to the first heat sink fins. Because the heat sink cavity is open and ventilated, the first heat sink fins can exchange heat with the outside environment, thus continuously dissipating heat from the first heat sink fins, which in turn cools the power cavity.

[0025] In one optional embodiment, the power cavity and the heat dissipation cavity are distributed along a first direction, which is perpendicular to the vertical direction. The heat sink further includes a second substrate and a second heat dissipation part. The second substrate and the first substrate are distributed along the vertical direction and fixedly connected. The second heat dissipation part extends outward from the second substrate. A third gas-liquid channel is provided in the second substrate. A fourth gas-liquid channel communicating with the third gas-liquid channel is provided in the second heat dissipation part. The third gas-liquid channel is isolated from the first gas-liquid channel. A second power device is provided on the side of the circuit board facing the opening. The second power device is in contact with the second substrate in the heat dissipation cavity. A cooling medium for gas-liquid conversion is provided in the third gas-liquid channel.

[0026] With a height difference between the first power device and the second power device, the second substrate and the second heat sink can better dissipate heat for the second power device, reducing the possibility that the power conversion device may be affected by excessive heat generation from the second power device. Furthermore, the power cavity and heat sink are distributed along the first direction, and the first substrate and the second substrate are distributed along the vertical direction, which can reduce the size of the heat sink in the first direction, thus reducing the size of the heat sink cavity in the first direction and consequently reducing the size of the power conversion device in the first direction.

[0027] In one optional embodiment, the power conversion device further includes a second heat exchanger for transferring heat from the power cavity to the heat dissipation cavity. Both the first and second heat exchangers are disposed within the heat dissipation cavity. The first and second heat dissipation portions are distributed vertically. The first substrate protrudes downward toward the first heat dissipation portion, and the second substrate protrudes downward toward the second heat dissipation portion. One of the first and second heat exchangers is located between the first and second heat dissipation portions, and the other is located below the one with the lower height of the first and second heat dissipation portions.

[0028] The hot air in the power cavity can exchange heat with the air in the heat dissipation cavity through the first and second heat exchangers, further reducing the temperature inside the power cavity and enabling the power conversion device to operate stably. Since the first substrate protrudes downwards from the first heat dissipation section, and the second substrate protrudes downwards from the second heat dissipation section, there is ample space below both the first and second heat dissipation sections. When installing the first and second heat exchangers, this ample space can be fully utilized, resulting in a more compact installation of the heat sink, the first heat exchanger, and the second heat exchanger. This maximizes the use of space within the heat dissipation cavity and reduces the size of the power device in the first direction.

[0029] In one optional embodiment, a first heat exchange channel is formed in the first heat exchanger, and a second heat exchange channel is formed in the second heat exchanger. The inlet of the first heat exchange channel and the inlet of the second heat exchange channel are both connected to a first connecting pipe. The outlet of the first heat exchange channel and the outlet of the heat exchange channel are both connected to the second connecting pipe. The first connecting pipe and the second connecting pipe are both located in the heat dissipation cavity and are both connected to the power cavity.

[0030] Hot air from the power chamber enters the first and second heat exchangers respectively through the first connecting pipe. After exchanging heat with the air in the heat dissipation chamber, the hot air in the first and second heat exchangers enters the second connecting pipe and returns to the power chamber. The first and second heat exchangers are interconnected and fixed together through the first and second connecting pipes, which improves the integration of the first and second heat exchangers. It eliminates the need to connect the first and second heat exchangers separately to the power chamber, facilitating unified assembly and disassembly of the first and second heat exchangers within the heat dissipation chamber.

[0031] In one optional embodiment, both the first heat exchange channel and the second heat exchange channel extend along the second direction, and the first connecting pipe and the second connecting pipe are respectively located on the lower of the first heat dissipation part and the second heat dissipation part, on different sides of the second direction, and the first direction, the second direction and the vertical direction are perpendicular to each other.

[0032] The first heat dissipation section, the first heat exchanger, the second heat dissipation section, and the second heat exchanger are alternately distributed. The space above and below the shorter of the first and second heat dissipation sections is utilized by the first and second heat exchangers, respectively. The spaces on both sides of the shorter of the first and second heat dissipation sections are utilized by the first and second connecting pipes, respectively. This layout allows for more efficient use of the heat dissipation cavity space, which is beneficial for reducing the size of power devices.

[0033] In one optional embodiment, the power conversion device further includes a protective cover, a heat dissipation cavity is formed inside the protective cover, and heat dissipation holes are provided on the protective cover. The heat dissipation holes include air inlets and air outlets. One of the air inlets and air outlets is located below the heat sink, and the other is located above the heat sink. A first fan is provided inside the heat dissipation cavity, and the first fan is used to drive the air entering through the air inlets to be discharged from the air outlets.

[0034] With the action of the first fan, the air outside the protective cover can enter through the air inlet and exit through the air outlet. The air inlet and air outlet are located on the upper and lower sides of the radiator, respectively, so that the outside air can pass through the radiator fully and improve the heat dissipation effect of the radiator.

[0035] In one optional embodiment, the first heat dissipation part includes a plurality of spaced-apart first condenser tubes, and the second heat dissipation part includes a plurality of spaced-apart second condenser tubes. A plurality of fins are provided between two adjacent first condenser tubes and between two adjacent second condenser tubes. In the first heat dissipation part and the second heat dissipation part, the number of fins provided in the one closer to the air inlet is less than the number of fins provided in the one farther from the air inlet.

[0036] The closer the air is to the air inlet, the lower the air temperature. When the air passes through the section of the first and second heat dissipation parts that is closer to the air inlet, heat exchange occurs, and the air temperature rises after heat exchange. In other words, within the heat dissipation chamber, the closer the air is to the air outlet, the higher the air temperature. The section of the first and second heat dissipation parts that is closer to the air inlet has sparser fins to allow a large amount of air to pass through, while the section that is farther from the air inlet has denser fins to enhance heat dissipation capacity. This allows the vertically arranged first and second heat dissipation parts to dissipate heat evenly.

[0037] In one optional embodiment, the dimension of the first heat dissipation part and the second heat dissipation part that is closer to the air inlet in the first direction is smaller than the dimension of the part that is farther from the air inlet in the first direction.

[0038] By employing an arrangement of varying lengths, more cool air can be directed to the part of the first and second heat dissipation sections that is farther from the air inlet, thereby enhancing the overall heat dissipation capacity of the radiator and balancing the heat dissipation of the first and second heat dissipation sections.

[0039] In one optional embodiment, the included angle between the first gas-liquid channel and the second gas-liquid channel is greater than 90 degrees and less than or equal to 160 degrees.

[0040] With the above design, when the first gas-liquid channel is arranged vertically, the second gas-liquid channel is inclined upwards from the first gas-liquid channel so that the liquid in the first heat dissipation part flows back into the first substrate, reducing the possibility of liquid cooling medium remaining in the first heat dissipation part.

[0041] In one optional embodiment, the first power device is fixedly connected to the first substrate by bolts. The circuit board is provided with a through hole for the head of the bolt to pass through. The shank of the bolt passes through the first power device and is threadedly connected to the first substrate. The head of the bolt abuts against the surface of the first power device away from the first substrate.

[0042] The first power device is fixedly connected to the first substrate, ensuring full contact between them and reducing the possibility of gaps between their contact surfaces. This close contact improves heat dissipation. Furthermore, the bolt head abuts against the first power device rather than the circuit board, minimizing the risk of damage during installation and reducing the impact on the circuit board when connecting the first power device and the first substrate.

[0043] In one alternative embodiment, a portion of the first substrate faces the surface of the partition, and the first substrate blocks at least a partial opening.

[0044] The heat dissipation cavity is connected to the outside world through heat dissipation holes. Impurities from the outside may enter the heat dissipation cavity. If impurities from the heat dissipation cavity enter the power cavity, they will affect the normal operation of the circuit board and its components (e.g., electronic devices). A portion of the first substrate is positioned directly opposite the partition plate, with a partial overlap between the first substrate and the partition plate. In this way, the first substrate can block at least part of the opening, reducing the possibility of gas in the heat dissipation cavity entering the power cavity through the opening. This also reduces the possibility of external impurities affecting the operation of the circuit board and its components, making the power cavity and heat dissipation cavity more independent of each other. A highly protected cavity (i.e., the power cavity) is formed within the power conversion equipment to house the circuit board, which is beneficial to the normal operation of the power conversion equipment.

[0045] In one optional embodiment, the inner wall surface of the first substrate forming the first gas-liquid channel includes a first wall surface and a second wall surface. The first wall surface and the second wall surface are disposed opposite to each other in the thickness direction of the first substrate. A plurality of support members are disposed between the first wall surface and the second wall surface. One end of each support member is connected to or abuts against the first wall surface, and the other end is connected to or abuts against the second wall surface.

[0046] The first substrate is hollow inside, and the support member serves to support the first and second walls. In other words, the internal cavity of the first substrate is supported by the support member, which reduces the possibility of the first substrate being flattened or bent, thus extending the life of the first substrate and reducing the possibility of the heat sink failing due to local deformation.

[0047] In one optional embodiment, the first substrate includes a base plate and a cover plate arranged along a first direction. The base plate is connected to a first power device, and the cover plate is located on the side of the base plate away from the first power device. The edge of the cover plate is fixedly connected to the edge of the base plate, and the cover plate bulges towards the side away from the base plate. A first gas-liquid channel is located between the cover plate and the base plate. One end of each support member is integrally connected to the base plate, and the other end is connected to or abuts against the cover plate. Multiple support members are divided into multiple rows of support groups arranged in a vertical direction. Each row of support groups includes multiple support members arranged in a second direction. The first direction, the second direction, and the vertical direction are perpendicular to each other. A flow equalization channel extending along the second direction is formed between two adjacent rows of support groups. The flow equalization channel is connected to the second gas-liquid channel. The upward-facing surfaces of multiple support members in each row of support groups are flush with each other, and the downward-facing surfaces of multiple support members in each row of support groups are flush with each other. The upward-facing and downward-facing surfaces of each support member are parallel.

[0048] The above design facilitates the extrusion molding of the base plate and its multiple support groups. For example, by producing the base plate and its multiple support groups through extrusion, and then dividing each support group into multiple support components through turning (or other processing methods), the production efficiency of the first substrate can be improved.

[0049] In one optional embodiment, the heat sink further includes a confluence section, which is disposed in the heat dissipation cavity and connected to the end of the first heat dissipation section away from the first substrate. The second gas-liquid channel includes a plurality of sub-channels, and the confluence section is provided with a confluence channel that communicates with different sub-channels in the second gas-liquid channel, so that the different sub-channels in the second gas-liquid channel are interconnected.

[0050] In some cases, the second gas-liquid channel has multiple different gas-liquid channels. The radiator is equipped with a confluence section, which allows the different gas-liquid channels in the second gas-liquid channel to be interconnected, so that the cooling working fluid in different gas-liquid channels can flow into the confluence section, which is beneficial to the condensation and reflux of the cooling working fluid.

[0051] In one optional embodiment, the radiator further includes a return pipe, which is disposed below the first heat dissipation part, with one end of the return pipe connected to the first gas-liquid channel and the other end connected to the confluence channel.

[0052] After the cooling medium condenses and dissipates heat in the first heat dissipation section, it gradually reverts to a liquid state. A portion of the liquid cooling medium flows back to the first substrate from the first heat dissipation section, while the remaining liquid coolant flows into the confluence channel of the manifold section, then into the return pipe, and finally back to the first substrate through the return pipe. The first substrate, the first heat dissipation section, the confluence section, and the return pipe are interconnected, reducing the possibility of liquid cooling medium remaining in the first heat dissipation section.

[0053] In one optional embodiment, the busbar includes a first plate and a second plate, the edges of the first plate and the second plate are fixedly connected, the first plate is connected to the end of the first heat dissipation part away from the first substrate, the second plate is located on the side of the first plate away from the first heat dissipation part, the second plate bulges towards the side away from the first plate, and the busbar channel is located between the first plate and the second plate; the second plate is provided with a plurality of concave structures, the plurality of concave structures are recessed into the busbar channel towards the direction close to the first plate, and the plurality of concave structures abut against the first plate.

[0054] The concave structure on the second plate is recessed into the confluence channel towards the first plate and abuts against the first plate. The concave structure can support the internal cavity (confluence channel) of the confluence part, reducing the possibility of the confluence channel being crushed by external forces and making the structure of the confluence part stronger.

[0055] In one optional embodiment, a first evaporation zone is provided in the first gas-liquid channel. The side of the first evaporation zone facing the first power device is connected to the inner wall surface of the first substrate. The outer wall surface of the first substrate corresponding to the inner wall surface connected to the first evaporation zone is in contact with the first power device. The first gas-liquid channel includes a first chamber and a second chamber located on both sides in the vertical direction of the first evaporation zone. The first evaporation zone is provided with a plurality of first flow channels connecting the first chamber and the second chamber.

[0056] The first power device abuts against the region of the first substrate where the first evaporation zone is formed. Heat from the first power device is transferred to the first evaporation zone through the first substrate. Because the first evaporation zone has multiple first flow channels, the contact area between the first evaporation zone and the cooling medium is increased, thus increasing the number of boiling nucleation points on the first evaporation zone. The cooling medium needs to flow between the first and second chambers through the first flow channels; that is, the cooling medium flows from below the first evaporation zone to above it through the first flow channels. More boiling nucleation points facilitate the transformation of the liquid cooling medium into a gaseous state.

[0057] In one optional embodiment, a second evaporation zone is provided on both sides of the first evaporation zone, the distribution direction of the two second evaporation zones is perpendicular to the vertical direction, and the second evaporation zone is provided with a plurality of second flow channels connecting the first chamber and the second chamber, the number of second flow channels on each second evaporation zone is less than the number of first flow channels.

[0058] Two second evaporation zones are located on either side of the first power device. Multiple second flow channels on the second evaporation zones increase the number of boiling nucleation points, facilitating the change of the cooling medium from liquid to gaseous state as it flows through. Because the second evaporation zones are farther from the first power device than the first evaporation zone, and the number of second flow channels on each second evaporation zone is less than the number of first flow channels, more cooling medium can pass through the first evaporation zone. Attached Figure Description

[0059] Figure 1 is a schematic diagram of the external structure of a power conversion device provided in an embodiment of this application;

[0060] Figure 2 is a schematic diagram of the internal chamber of a power conversion device provided in an embodiment of this application;

[0061] Figure 3 is a schematic diagram of the internal structure of the heat dissipation cavity of the first power conversion device provided in the embodiment of this application;

[0062] Figure 4 is a partial exploded view of a power conversion device provided in an embodiment of this application;

[0063] Figure 5 is a schematic diagram of the internal structure of a radiator provided in an embodiment of this application;

[0064] Figure 6 is an enlarged view of point A in Figure 4;

[0065] Figure 7 is a schematic diagram of the internal structure of another heat sink provided in an embodiment of this application;

[0066] Figure 8 is a schematic diagram of a fin installation method provided in an embodiment of this application;

[0067] Figure 9 is a partial structural schematic diagram of a fin provided in an embodiment of this application;

[0068] Figure 10 is a schematic diagram of a busbar provided in an embodiment of this application;

[0069] Figure 11 is a schematic diagram of the structure of a first plate and a second plate provided in an embodiment of this application;

[0070] Figure 12 is a schematic diagram of another busbar structure provided in an embodiment of this application;

[0071] Figure 13 is a schematic diagram of a reflux pipe provided in an embodiment of this application;

[0072] Figure 14 is a schematic diagram of the structure of a first evaporation zone provided in an embodiment of this application;

[0073] Figure 15 is a schematic diagram of another first evaporation zone provided in an embodiment of this application;

[0074] Figure 16 is a schematic diagram of a support group provided in an embodiment of this application;

[0075] Figure 17 is a structural schematic diagram of a cover plate and a bottom plate provided in an embodiment of this application;

[0076] Figure 18 is a schematic diagram of a threaded hole provided in an embodiment of this application;

[0077] Figure 19 is a schematic diagram of another threaded hole provided in an embodiment of this application;

[0078] Figure 20 is a schematic diagram of another type of threaded hole provided in an embodiment of this application;

[0079] Figure 21 is a schematic diagram of the internal structure of the heat dissipation cavity of the second power conversion device provided in the embodiment of this application;

[0080] Figure 22 is a schematic diagram of the internal structure of the heat dissipation cavity of the third power conversion device provided in the embodiment of this application;

[0081] Figure 23 is a schematic diagram of the internal structure of the heat dissipation cavity of the fourth power conversion device provided in the embodiment of this application;

[0082] Figure 24 is a partial exploded view of the fourth power conversion device provided in the embodiment of this application;

[0083] Figure 25 is a schematic diagram of another heat sink provided in an embodiment of this application;

[0084] Figure 26 is a schematic diagram of another type of radiator provided in an embodiment of this application;

[0085] Figure 27 is a schematic diagram of the structure of a first connecting pipe and a second connecting pipe provided in an embodiment of this application;

[0086] Figure 28 is a schematic diagram of the internal structure of the heat dissipation cavity of the fifth power conversion device provided in the embodiment of this application;

[0087] Figure 29 is a partial exploded view of the fifth power conversion device provided in the embodiments of this application;

[0088] Figure 30 is a schematic diagram of the internal structure of the heat dissipation cavity of the sixth power conversion device provided in the embodiment of this application;

[0089] Figure 31 is a schematic diagram showing the positions of various first heat exchangers provided in the embodiments of this application.

[0090] Reference numerals: 100-Power conversion device; 1-Housing; 11-Baffle; 111-Power cavity; 112-Heat dissipation cavity; 113-Opening; 114-Mounting port; 115-Through port; 12-Protective cover; 121-Heat dissipation hole; 1211-Air inlet; 1212-Air outlet; 2-Circuit board; 21-First power device; 211-Bolt; 2111-Head; 2112-Ring; 22-Through hole; 23-Second power device; 24-Inductor; 25-Electronic component; 3-Radiator; 31-First substrate; 310-First gas-liquid channel; 311-First wall; 312-Second wall; 313-Support member; 3131-Support assembly; 3132-Flow equalization channel; 314-First evaporation zone; 3141-First flow channel; 3142-Protrusion; 315-Second evaporation zone; 3151-Second flow channel; 316-First chamber; 317-Second chamber; 318-Base plate; 3181-Threaded hole; 319-Cover plate; 3191-Boss; 32-First Heat dissipation section; 320-Second gas-liquid channel; 321-First condenser tube; 3211-Sub-channel; 33-Accommodation space; 34-Fin; 341-Bending section; 342-Ventilation channel; 35-Gathering section; 350-Gathering channel; 3501-First plate; 351-Second plate; 3511-Concave structure; 352-Gathering tube; 353-Return tube; 36-Second substrate; 360-Third gas-liquid channel; 37-Second heat dissipation section; 370-Fourth gas-liquid channel; 371-Second condenser tube; 4-First heat exchanger; 41-First flat heat dissipation tube; 42-First heat sink; 43-Heat conduction plate; 44-Heat dissipation fin; 441-First heat dissipation fin; 442-Second heat dissipation fin; 5-Second heat exchanger; 51-First flat heat dissipation tube; 22-First heat sink; 6-First connecting pipe; 61-Heat exchange inlet; 7-Second connecting pipe; 71-Heat exchange outlet; 8-First fan; 9-Second fan. Detailed Implementation

[0091] The technical solutions of the embodiments of this application will be described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments.

[0092] In this application, unless otherwise expressly specified and limited, the terms "upper" and "lower" and other terms indicating orientation or positional relationship may be defined relative to the orientation in which the components are schematically placed in the accompanying drawings. These directional terms may be relative concepts, used for relative description and clarification, and may change accordingly depending on the orientation of the components in the accompanying drawings. They should not be construed as limitations on this application.

[0093] In this application, the terms "first," "second," etc., are used for descriptive purposes only to distinguish one element from another, and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first," "second," etc., may explicitly or implicitly include one or more of that feature.

[0094] In this application, unless otherwise expressly stated and limited, "multiple" means two or more.

[0095] In this application, unless otherwise expressly specified and limited, the terms "installation," "connection," and "linkage" should be interpreted broadly. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to mechanical connections or electrical connections; they can refer to direct connections or indirect connections through an intermediate medium; and they can refer to the internal connection between two components. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances. Furthermore, when describing pipelines or channels, the terms "connection" and "linkage" as used in this application have the meaning of establishing electrical conductivity. The specific meaning needs to be understood in conjunction with the context.

[0096] Furthermore, in this application, the terms "exemplary" or "for example" are used to indicate that something is an example, illustration, or illustration. Any embodiment or design described as "exemplary" or "for example" in this application should not be construed as being more preferred or advantageous than other embodiments or designs. Specifically, the use of terms such as "exemplary" or "for example" is intended to present the relevant concepts in a specific manner.

[0097] In the accompanying drawings of the embodiments of this application, solid structures such as parts and components are represented by guide lines; hollow structures such as openings, holes, spaces, and cavities are represented by guide lines with arrows.

[0098] This application provides a power conversion device 100, which includes, for example, a photovoltaic inverter, particularly a string photovoltaic inverter with a power rating of 400 kilowatts or higher. When the single-unit power of the photovoltaic inverter reaches 400 kilowatts or more, traditional physical structure-based heat dissipation solutions are no longer sufficient to meet the heat dissipation requirements of such high-power devices. New and more powerful heat dissipation solutions are needed to meet these new challenges. This application, for instance, introduces two-phase heat dissipation technology into the photovoltaic inverter. Through the gas-liquid exchange of the heat-conducting medium inside and outside the power cavity, the heat from the power devices of the ultra-high-power photovoltaic inverter is dissipated effectively and promptly, thereby ensuring the long-term stable operation of the power conversion device 100.

[0099] Figure 1 illustrates the external structure of the power conversion device 100, and Figure 2 illustrates the internal chamber of the power conversion device 100. As shown in Figures 1 and 2, when the power conversion device 100 is a photovoltaic inverter, it is vertically installed. In the vertical direction, various input interfaces are installed on the bottom of the power conversion device 100, including a large number of photovoltaic input terminals and communication ports.

[0100] Referring to Figures 1 and 2, the power conversion device 100 includes a housing 1. The housing 1 may include a cabinet-like structure (e.g., a cabinet), a box-like structure (e.g., a chassis), etc. This application does not impose specific limitations on the shape of the housing 1. The housing 1 includes a partition 11. For example, the partition 11 includes a side wall (or side plate, outer shell plate) on one side of the housing 1, that is, the partition 11 is part of the housing 1. A sealed power cavity 111 is formed inside the housing 1, and an open and ventilated heat dissipation cavity 112 is formed outside the housing 1. The partition 11 is located between the power cavity 111 and the heat dissipation cavity 112. That is, the power cavity 111 is the internal chamber of the housing 1, and the heat dissipation cavity 112 is located outside the housing 1.

[0101] The heat dissipation cavity 112 can be formed by providing a protective cover 12 outside the housing 1. For example, referring to Figures 1 and 2, the power conversion device 100 also includes a protective cover 12, with the heat dissipation cavity 112 formed inside the protective cover 12. The power cavity 111 and the heat dissipation cavity 112 are distributed along a first direction, which is perpendicular to the vertical direction. The protective cover 12 is provided with heat dissipation holes 121 that communicate with the internal heat dissipation cavity 112. In some examples, the protective cover 12 has a hollow structure, and the heat dissipation holes 121 include holes on the hollow protective cover 12. In the examples in Figures 1 and 2, the heat dissipation holes 121 are provided in a partial area of ​​the protective cover 12. In other examples, the heat dissipation holes 121 can be provided in the entire area of ​​each wall of the protective cover 12. This application does not impose specific limitations on this.

[0102] Referring to Figure 2, the power conversion device 100 also includes a circuit board 2, such as a printed circuit board (PCB). The circuit board 2 is disposed within the power cavity 111, and the circuit board 2 may be arranged parallel to the partition 11. Multiple devices are disposed on the circuit board 2. In order to protect the circuit board 2 and the devices thereon, the protection level of the power cavity 111 is higher than that of the heat dissipation cavity 112. For example, the IP (Ingress Protection) protection level of the power cavity 111 is higher than that of the heat dissipation cavity 112.

[0103] The devices disposed on the circuit board 2 include at least one of chips, resistors, capacitors, diodes, and transistors. Multiple devices may be disposed on the same side of the circuit board 2, or a portion of the multiple devices may be disposed on the side of the circuit board 2 away from the partition 11. For example, multiple electronic devices 25 (including but not limited to capacitors, inductors, relays, etc.) may be disposed on the side of the circuit board 2 away from the partition 11, and another portion of the multiple devices may be disposed on the side of the circuit board 2 closer to the partition 11.

[0104] In this application, multiple devices are arranged on both sides of the circuit board 2 as an example. Figure 3 shows the internal structure of the power conversion device 100, and Figure 4 shows an exploded view of a partial structure of the power conversion device 100. Referring to Figures 3 and 4, the partition 11 is provided with an opening 113, which connects the power cavity 111 and the heat dissipation cavity 112. The opening 113 includes a square opening or a circular opening.

[0105] A first power device 21 is disposed on the side of circuit board 2 facing opening 113. The first power device 21 constitutes the power conversion circuit of power conversion device 100 to convert the DC power input to power conversion device 100. For example, the first power device 21 includes a power module or multiple sets of power switching transistors. In some examples, the first power device 21 includes devices on circuit board 2 that generate significant heat. One end of the first power device 21 connected to circuit board 2 is located inside power cavity 111, and the other end of the first power device 21, away from circuit board 2, extends towards heat dissipation cavity 112. The first power device 21 and multiple other devices on circuit board 2 are respectively mounted on two opposite sides of circuit board 2, separated by circuit board 2, thereby preventing heat from the first power device 21 from being transferred into the power cavity 111 on the other side of circuit board 2, thus avoiding temperature increases within the power cavity 111 and causing thermal contamination to other devices requiring protection.

[0106] As can be seen, the heat dissipation scheme of the power conversion device 100 in this application embodiment is based on hierarchical and classified heat dissipation. That is, different heat dissipation methods and heat conduction paths are designed for the high-heat first power device 21, the low-heat electronic device 25 that requires high protection, and the high-heat inductor device. The core of the heat dissipation scheme is a two-phase enhanced heat dissipation method to dissipate heat and protect the core device and the core heat source. For example, the first power device 21 is subjected to high-intensity internal and external two-phase conversion heat dissipation to ensure that the heat of the entire device is well resolved. At the same time, various electronic components are also protected at different levels according to their characteristics.

[0107] Referring to Figures 3 and 4, the power conversion device 100 further includes a heat sink 3, which is disposed in a heat dissipation cavity 112. The heat sink 3 includes a first substrate 31 and a first heat dissipation part 32 that are connected to the internal cavity. The first substrate 31 extends vertically and protrudes from the first heat dissipation part 32. For example, the first substrate 31 protrudes downward toward the first heat dissipation part 32. The first substrate 31 is disposed at the opening 113. The first power device 21 is located inside the power cavity 111 and is in thermal contact with the first substrate 31. The first heat dissipation part 32 is disposed on the side of the first substrate 31 away from the partition 11.

[0108] Figure 5 illustrates the internal structure of the radiator 3. A first gas-liquid channel 310 is provided in the first substrate 31, and a second gas-liquid channel 320 communicating with the first gas-liquid channel 310 is provided in the first heat dissipation part 32. The internal cavity of the first substrate 31 is provided with a cooling medium for gas-liquid conversion. The cooling medium includes water or other refrigerants capable of gas-liquid conversion.

[0109] When the first power device 21 heats up, the heat from the first power device 21 is transferred to the first substrate 31, heating the cooling medium inside the first substrate 31. When the liquid cooling medium is heated, at least a portion of it becomes gaseous. The gaseous cooling medium flows into the first heat dissipation section 32, that is, from the first gas-liquid channel 310 into the second gas-liquid channel 320. The heat dissipation holes 121 on the housing 1, which communicate with the heat dissipation cavity 112 (see Figure 2 for reference), facilitate heat exchange between the cooling medium inside the first heat dissipation section 32 and the outside environment. This causes the gaseous cooling medium to condense and dissipate heat within the first heat dissipation section 32, gradually turning back into a liquid state. It then flows back from the second gas-liquid channel 320 into the first gas-liquid channel 310 of the first substrate 31, thus continuously dissipating heat for the first power device 21. By providing targeted heat dissipation for the first power device 21, the power conversion device 100 can operate stably.

[0110] To effectively dissipate heat, the heat dissipation cavity 112 is connected to the outside through the heat dissipation hole 121. The partition 11 can reduce the possibility of impurities from the heat dissipation cavity 112 or the outside entering the power cavity 111. Furthermore, the first substrate 31 is disposed at the opening 113. Even if the first substrate 31 comes into contact with the first power device 21, it can also block the opening 113, further reducing the possibility of mutual interference between the heat dissipation cavity 112 and the power cavity 111. This allows the circuit board 2 to be placed in the relatively well-protected power cavity 111. While dissipating heat from the first power device 21, this also ensures the safety of other devices (e.g., multiple electronic devices 25) and reduces the possibility of the power conversion device 100 malfunctioning.

[0111] Referring to Figures 3 and 4, in one example, the edge of the first substrate 31 faces the surface of the partition 11, and the first substrate 31 blocks the opening 113. It should be noted that the part of the surface of the first substrate 31 facing the surface of the partition 11 means that the first substrate 31 and the partition 11 overlap in the first direction. With this overlap, the first substrate 31 can abut against the partition 11. Even if it doesn't abut, the overlap between the first substrate 31 and the partition 11 better blocks the opening 113, reducing the possibility of gas in the heat dissipation cavity 112 entering the power cavity 111 through the opening 113. This also reduces the possibility of external impurities affecting the operation of the circuit board 2 and the devices on it, making the power cavity 111 and the heat dissipation cavity 112 more independent of each other. A highly protected cavity (power cavity 111) is formed within the power conversion device 100 to house the circuit board 2, which is beneficial to the normal operation of the power conversion device 100.

[0112] To improve heat dissipation, the first power device 21 is located at least partially below the first heat dissipation part 32. In the example shown in FIG5, a portion of the first power device 21 extends below the first heat dissipation part 32 and makes thermal contact with the portion of the first substrate 31 that protrudes below the first heat dissipation part 32. Another portion of the first power device 21 faces the first heat dissipation part 32 in the first direction, so that the overlap area between the first heat dissipation part 32 and the first power device 21 in the first direction is small. The first heat dissipation part 32 will have more area to exchange heat with the air in the heat dissipation cavity 112, which is beneficial to improving the heat dissipation effect of the heat sink 3.

[0113] In other examples, the first power device 21 is located entirely below the first heat sink 32 and makes thermally conductive contact with the portion of the first substrate 31 that protrudes below the first heat sink 32. That is, the first power device 21 and the first heat sink 32 are located on opposite sides of the first substrate 31, and the first power device 21 and the first heat sink 32 are spaced apart in the vertical direction, or in other words, the first power device 21 and the first heat sink 32 do not overlap in the first direction.

[0114] Regarding the structure of the first substrate 31, in one example provided in this application, referring to Figures 4 and 5, the first substrate 31 is a square plate structure. In other examples, the first substrate 31 may also be disc-shaped or other irregularly shaped plates without a distinct shape; this application does not impose any limitations on this.

[0115] The first heat dissipation part 32 has a structure that can perform condensation. For example, the first heat dissipation part 32 is a microchannel condenser with heat sinks. Figure 6 is an enlarged view of point A in Figure 4. Referring to Figures 5 and 6, the first heat dissipation part 32 includes a plurality of first condensing tubes 321 spaced apart along the second direction. The first direction, the second direction and the vertical direction are perpendicular to each other. In the example shown in Figure 5, each first condensing tube 321 can be a microchannel flat tube. The plurality of sub-channels 3211 in each first condensing tube 321 (that is, the microchannels in the microchannel flat tube) are arranged in the vertical direction, and each sub-channel 3211 extends along the first direction.

[0116] It should be noted that the aforementioned sub-channels 3211 are channels for the flow of cooling working fluid, and this application does not limit the size and structure of the sub-channels 3211. Multiple sub-channels 3211 in each first condenser tube 321 form the internal chamber of that first condenser tube 321, and the internal chambers of multiple first condenser tubes 321 form the second gas-liquid channel 320 of the first heat dissipation section 32. In other examples, the first condenser tube 321 may not be a plate-shaped tube with multiple internal channels, but rather a plate-shaped tube with a complete internal chamber, or a tortuous pipe; this application does not impose any restrictions on this.

[0117] In one example, referring to Figure 6, multiple fins 34 are provided between two adjacent first condenser tubes 321. In other examples, fins 34 may not be provided.

[0118] After the cooling medium in the first heat dissipation section 32 becomes liquid, it needs to flow back into the first substrate 31. To facilitate the return of the cooling medium in the first heat dissipation section 32 to the first substrate 31, in some examples, referring to FIG7, FIG7 exemplarily shows another structure of the first heat dissipation section 32, in which the first heat dissipation section 32 can be inclined. For example, the included angle α between the first gas-liquid channel 310 and the second gas-liquid channel 320 is greater than 90 degrees and less than 180 degrees, wherein the included angle α includes 95 degrees, 120 degrees, 150 degrees, 160 degrees or 170 degrees, or the included angle α is within the range of these angles. As another example, the included angle α between the first gas-liquid channel 310 and the second gas-liquid channel 320 is greater than 90 degrees and less than or equal to 160 degrees, wherein the included angle α includes 110 degrees, 130 degrees, 140 degrees, 160 degrees, etc., or the included angle α is within the range of these angles. By forming a specific angle between the first gas-liquid channel 310 and the second gas-liquid channel 320, the cooling fluid can be smoothly returned to the position in the first substrate 31 near the thermally conductive contact with the first power device 21 under the action of gravity.

[0119] When the first heat dissipation section 32 needs to be tilted, in an example where the first heat dissipation section 32 includes a plurality of first condenser tubes 321 (e.g., a microchannel flat tube structure), the first condenser tubes 321 are flat tubes similar to a parallelogram structure, and each sub-channel 3211 is tilted obliquely upward from the first substrate 31 in a first direction so that the liquid in the first heat dissipation section 32 flows back to the first substrate 31, reducing the possibility that the liquid cooling medium will remain in the first heat dissipation section 32.

[0120] In the example shown in Figure 5, the included angle α between the first gas-liquid channel 310 and the second gas-liquid channel 320 is also 90 degrees, that is, the first gas-liquid channel 310 and the second gas-liquid channel 320 are perpendicular to each other.

[0121] In some examples, when multiple fins 34 are arranged between two adjacent first condenser tubes 321, the installation method of the fins 34 is adjusted to allow the airflow to better dissipate heat from the fins 34. Taking the first heat dissipation part 32 being inclined as an example, the installation method of the fins 34 is described. Figure 8 shows an exemplary installation method of the fins 34, and Figure 9 shows a partial structure of the fins 34 in Figure 8. Referring to Figure 9, multiple fins 34 between two adjacent first condenser tubes 321 are arranged along a first direction, and two adjacent fins 34 are integrally connected by a bending section 341 between the two fins 34, so that the multiple fins 34 and the multiple bending sections between two adjacent first condenser tubes 321 form a corrugated plate-like structure (two adjacent fins 34 may also not be connected, such as the fin 34 scheme in Figure 6). The device includes a ventilation channel 342 between adjacent fins 34, which is parallel to the ventilation direction. For example, referring to Figure 8, the power conversion device 100 also includes a first fan 8 (the position of the first fan 8 can also be seen in Figures 3 and 4). The first fan 8 can be positioned below the ventilation channel 342. Under the action of the first fan 8, the airflow passes through the first heat dissipation section 32 in a vertical direction (arrow X1 indicates the airflow direction). In this case, the ventilation channel 342 extends vertically (dashed line L1 indicates the extension direction of the ventilation channel 342), or in other words, the extension direction of the ventilation channel 342 is parallel to the surface of the substrate 31 (dashed line L1 is parallel to dashed line L2). This design reduces the resistance of the airflow through the first heat dissipation section 32 and also reduces the possibility of the ventilation channel 342 being blocked by dust, thereby improving the heat dissipation effect of the heat sink 3.

[0122] Furthermore, to facilitate the return of the cooling working fluid, the radiator 3 may also include a confluence section 35. Figures 5 and 7 show the positions of the confluence section 35 in two examples. The confluence section 35 is located on the side of the first heat dissipation section 32 away from the first substrate 31. A confluence channel 350 is provided in the confluence section 35, and the confluence channel 350 of the confluence section 35 communicates with the second gas-liquid channel 320 of the first heat dissipation section 32. When the first heat dissipation section 32 includes a plurality of first condenser tubes 321, and each first condenser tube 321 includes a plurality of sub-channels 3211 (refer to the description of this above for further information), the confluence channel 350 communicates with different sub-channels 3211 in the second gas-liquid channel 320, so that the different sub-channels 3211 in the second gas-liquid channel 320 are interconnected through the confluence channel 350. When the cooling medium condenses and dissipates heat in the first heat dissipation section 32, it gradually turns back into a liquid cooling medium. A portion of the liquid cooling medium flows directly from the first heat dissipation section 32 back to the first substrate 31 without entering the confluence section 35, while another portion of the liquid cooling medium flows into the confluence channel 350 of the confluence section 35, then flows downward from the confluence channel 350, and then flows back to the first substrate 31 through the bottom of the second gas-liquid channel 320, which is beneficial for the condensation and return of the cooling medium.

[0123] Figure 10 illustrates an exemplary structure of a junction 35, which may include a first plate 3501 and a second plate 351. Figure 11 illustrates an exemplary structure of the first plate 3501 and the second plate 351. Referring to Figures 10 and 11, the edge of the first plate 3501 is fixedly connected to the edge of the second plate 351 (e.g., welded). The first plate 3501 (which is shielded by the second plate 351 in Figure 10 and is located behind the second plate 351) is connected to the first heat dissipation part 32. The second plate 351 is located on the side of the first plate 3501 away from the first heat dissipation part 32. The second plate 351 bulges toward the side away from the first plate 3501, so that the first plate 3501 and the second plate 351 form a junction channel 350. Furthermore, multiple concave structures 3511 can be provided on the second plate 351. These concave structures 3511 are recessed into the confluence channel 350 in a direction close to the first plate 3501 and abut against the first plate 3501 to provide support and reduce the possibility of the internal chamber of the confluence section 35 being crushed.

[0124] Figure 12 illustrates an alternative structure of the manifold 35. In the example shown in Figure 12, the first heat dissipation section 32 includes a plurality of first condenser tubes 321, and the manifold 35 includes a plurality of manifolds 352. Each manifold 352 is connected to a different sub-channel 3211 of a first condenser tube 321 (the structure of the sub-channel 3211 is shown in Figures 5 and 7 for reference). The internal spaces of all manifolds 352 form a manifold channel 350. In other examples, each manifold 352 is a solid tube.

[0125] Figure 13 illustrates another possible structure of the manifold 35. Referring to Figure 13, the manifold 35 is constructed as a hollow plate or a hollow box-shaped structure. In this example, a support structure can also be provided within the manifold channel 350 of the manifold 35. This support structure serves the same function as the recessed structure 3511 in Figure 10. The difference between this support structure and the recessed structure 3511 in Figure 10 is that the recessed structure 3511 in Figure 10 is formed directly on the second plate 351 during processing by applying local pressure or by other processing methods. The support structure in the example of Figure 13 is separately provided (e.g., welded later) to strengthen the support. The example shown in Figure 13 is another example without a support structure.

[0126] In some examples, the heat sink 3 also includes a return pipe 353. Taking the confluence section 35 shown in FIG13 as an example, the return pipe 353 is disposed below the first heat sink 32. One end of the return pipe 353 is connected to the first gas-liquid channel 310 in the first substrate 31, and the other end is connected to the confluence channel 350 in the confluence section 35. The positions of the first gas-liquid channel 310 and the confluence channel 350 can be referred to FIG5 or FIG7. Multiple return pipes 353 may be provided and spaced apart along the second direction.

[0127] In the above example, after the cooling medium condenses and dissipates heat in the first heat dissipation section 32, it gradually returns to a liquid state. A portion of the liquid cooling medium flows back to the first substrate 31 through the second gas-liquid channel 320 of the first heat dissipation section 32, while another portion flows into the confluence section 35, then enters the return pipe 353 through the confluence channel 350, and finally flows back to the first substrate 31 through the return pipe 353. The first substrate 31, the first heat dissipation section 32, the confluence section 35, and the return pipe 353 are interconnected, reducing the possibility of the liquid cooling medium remaining in the first heat dissipation section 32.

[0128] Furthermore, to facilitate evaporation, the structure of the first substrate 31 can be improved. For example, Figure 14 shows an exemplary structure of another first substrate 31. Referring to Figure 14, a first evaporation band 314 is provided in the first gas-liquid channel 310 of the first substrate 31. The first evaporation band 314 is disposed opposite to the first power device 21 in a first direction (the position of the first power device 21 can be referred to Figure 5 or Figure 7). The side of the first evaporation band 314 facing the first power device 21 is connected to the inner wall surface of the first substrate 31. The outer wall surface of the first substrate 31 corresponding to the inner wall surface connected to the first evaporation band 314 is in contact with the first power device 21. That is, the area of ​​the first substrate 31 where the first evaporation band 314 is provided is the area of ​​the first substrate 31 in contact with the first power device 21.

[0129] The first gas-liquid channel 310 inside the first substrate 31 includes a first chamber 316 and a second chamber 317 located on both sides of the first evaporation zone 314 in the vertical direction. The first evaporation zone 314 is provided with a plurality of first flow channels 3141 connecting the first chamber 316 and the second chamber 317. It can be understood that the first flow channels 3141 also belong to the first gas-liquid channel 310. In the example shown in FIG14, the first flow channel 3141 can be a groove formed on the first evaporation zone 314, each groove extending in the vertical direction, so that each first flow channel 3141 extends in the vertical direction, thereby connecting the first chamber 316 and the second chamber 317 distributed in the vertical direction. The plurality of first flow channels 3141 are spaced apart in the second direction.

[0130] Since the first power device 21 abuts against the area where the first evaporation zone 314 is formed on the first substrate 31, the heat on the first power device 21 is transferred to the first evaporation zone 314 through the first substrate 31. The first evaporation zone 314 has multiple first flow channels 3141, which increases the surface area of ​​the first evaporation zone 314, resulting in a larger contact area between the first evaporation zone 314 and the cooling medium, thus increasing the number of boiling nucleation points on the first evaporation zone 314. The cooling medium needs to flow through the first flow channels 3141 between the first chamber 316 and the second chamber 317; that is, the cooling medium flows from below the first evaporation zone 314 through the first flow channels 3141 into the upper part of the first evaporation zone 314. More boiling nucleation points facilitate the transformation of the liquid cooling medium into a gaseous state.

[0131] In the example shown in Figure 14, the first evaporation band 314 is formed by providing multiple first flow channels 3141 (groove-like structures) on a protruding structure inside the first substrate 31, making the first evaporation band 314 resemble a dense toothed structure. The inner wall surface of the first substrate 31 forming the first gas-liquid channel 310 includes a first wall surface 311 and a second wall surface 312. Figure 14 only shows the first wall surface 311 (the wall surface near the first power device 21) as an example. The second wall surface 312 can be further referenced in Figure 5. The first wall surface 311 and the second wall surface 312 are arranged opposite each other in the thickness direction (first direction) of the first substrate 31. The first evaporation band 314 can be integrally connected to the first wall surface 311, allowing the heat from the first power device 21 to be quickly transferred to the first evaporation band 314. In other examples, the first evaporation band 314 may include multiple heat-conducting plates (e.g., fins), which are spaced apart along a second direction, with a first flow channel 3141 formed between adjacent heat-conducting plates.

[0132] In other examples, referring to Figure 15, which exemplarily illustrates another structure of the first evaporation zone 314, the first evaporation zone 314 includes a plurality of matrix-arranged protrusions 3142, and any channel formed by the plurality of matrix-arranged protrusions 3142 that can connect the first chamber 316 and the second chamber 317 is a first flow channel 3141. In this example, the first evaporation zone 314 can also be integrally connected to the first wall surface 311.

[0133] In other examples, the first evaporation belt 314 is a corrugated plate with multiple bends. In this example, the first evaporation belt 314 is an independent structure and is mounted on the first substrate 31. The first evaporation belt 314 is then connected to the inner wall of the first substrate 31 by subsequent welding (or other connection methods).

[0134] In some examples, referring to Figures 14 and 15, second evaporation zones 315 are provided on both sides of the first evaporation zone 314, and the distribution direction (second direction) of the two second evaporation zones 315 is perpendicular to the vertical direction. The second evaporation zone 315 is provided with multiple second flow channels 3151 connecting the first chamber 316 and the second chamber 317. It can be understood that the second flow channels 3151 also belong to the first gas-liquid channel 310. Providing the second flow channels 3151 increases the surface area of ​​the second evaporation zone 315, thereby increasing the number of boiling nucleation points. When the cooling medium flows through the second flow channels 3151, it facilitates the change of the cooling medium from a liquid state to a gaseous state.

[0135] The second evaporation zone 315 is farther from the first power device 21, while the first evaporation zone 314 is closer to the first power device 21. This allows the number of second flow channels 3151 on each second evaporation zone 315 to be less than the number of first flow channels 3141 (the first flow channels 3141 are more densely packed). As a result, more cooling medium passes through the first evaporation zone 314, which is beneficial for the cooling medium to absorb heat from the first power device 21. After absorbing heat from the first power device 21, the liquid cooling medium in the second chamber 317 turns into a gaseous state and enters the first chamber 316 through the first flow channel 3141. The cooled and liquefied cooling medium can flow back into the second chamber 317 through the second flow channel 3151.

[0136] Since a first gas-liquid channel 310 is provided within the first substrate 31, in order to reduce the possibility of deformation of the first substrate 31, in some examples, referring to Figures 14 and 15, the inner wall surface of the first substrate 31 surrounding the first gas-liquid channel 310 includes a first wall surface 311 and a second wall surface 312. Figures 14 and 15 only exemplarily show the first wall surface 311 (the wall surface near the first power device 21). The second wall surface 312 can be further illustrated in Figure 5. The first wall surface 311 and the second wall surface 312 are arranged opposite each other in the thickness direction (first direction) of the first substrate 31. A plurality of support members 313 are provided between the first wall surface 311 and the second wall surface 312. One end of each support member 313 is connected to or abuts against the first wall surface 311, and the other end is connected to or abuts against the second wall surface 312. For example, both ends of each support member 313 are connected to the first wall surface 311 and the second wall surface 312, respectively.

[0137] Among them, the support member 313 is a protruding post (protrusion) or other protruding support structure. The support member 313 plays the role of supporting the first wall surface 311 and the second wall surface 312 between the first wall surface 311 and the second wall surface 312. That is, the internal cavity (first gas-liquid channel 310) of the first substrate 31 is supported by the support member 313, which reduces the possibility of the first substrate 31 being flattened or bent, makes the life of the first substrate 31 longer, and also reduces the possibility of the heat sink 3 failing due to local deformation.

[0138] In the two examples shown in Figures 14 and 15, the first chamber 316 has a relatively large space, and multiple support members 313 can be disposed within the first chamber 316. In other examples, such as those without the first evaporation zone 314 and the second evaporation zone 315, the support members 313 can be disposed at any suitable location to support the first substrate 31.

[0139] In some examples, multiple supports 313 are divided into multiple rows of support groups 3131 arranged vertically. Figure 16 illustrates an exemplary structure of a support group 3131. Referring to Figure 16, each row of support groups 3131 includes multiple supports 313 arranged along a second direction. A flow equalization channel 3132 for the flow of cooling working fluid is formed between adjacent rows of support groups 3131. The flow equalization channel 3132 extends along the second direction and communicates with a second gas-liquid channel 320 (refer to Figure 7 for further details), so that the cooling working fluid in the flow equalization channel 3132 can flow to multiple regions of the second gas-liquid channel 320 in the second direction. For example, when the first heat dissipation section 32 includes a plurality of first condenser tubes 321 spaced apart along the second direction (for example, the dashed box marked "321" represents the installation position of one of the first condenser tubes 321), the flow equalization channel 3132 is connected to the plurality of first condenser tubes 321, so that the gaseous cooling medium can enter the plurality of first condenser tubes 321 for cooling, reducing the possibility that the cooling medium is concentrated in individual first condenser tubes 321.

[0140] To facilitate the manufacturing of the first substrate 31, it can be divided into multiple parts for separate production and then assembled together. In some examples, the first substrate 31 includes a base plate 318 and a cover plate 319 arranged along a first direction. Figure 17 exemplarily illustrates the structure of a base plate 318 and a cover plate 319. Referring to Figure 17, the base plate 318 is connected to the first power device 21, and the cover plate 319 is located on the side of the base plate 318 away from the first power device 21. The edge of the cover plate 319 is fixedly connected to the edge of the base plate 318, and the cover plate 319 bulges towards the side away from the base plate 318. A first gas-liquid channel 310 is located between the base plate 318 and the cover plate 319. Each support member 313 has one end integrally connected to the base plate 318 and the other end connected to or abutting against the cover plate 319.

[0141] Furthermore, referring to Figure 16, on the base plate 318, the vertically upward-facing surfaces of the multiple support members 313 in each row of support groups 3131 are flush (for example, the vertically upward-facing surfaces of the multiple support members 313 in one row of support groups 3131 are all parallel to the dashed line L3), and the downward-facing surfaces of the multiple support members 313 in each row of support groups 3131 are flush (for example, the vertically downward-facing surfaces of the multiple support members 313 in one row of support groups 3131 are all parallel to the dashed line L4), and the vertically upward-facing and downward-facing surfaces of each support member 313 are parallel. In this way, the base plate 318 and the multiple support groups 3131 thereon can be produced by extrusion molding, and each support group 3131 can be divided into multiple support members 313 by turning (or other processing methods), which helps to improve the production efficiency of the first substrate 31.

[0142] Furthermore, referring to Figures 16 and 17, when a first evaporation zone 314 and a second evaporation zone 315 are provided in the first gas-liquid channel 310, the first evaporation zone 314 and the second evaporation zone 315 can also be integrally connected to the base plate 318. In some examples, the surface of the first evaporation zone 314 facing the first chamber 316 (the vertically upward surface) is flush with the surface of each second evaporation zone 315 facing the first chamber 316 (the vertically upward surface) (e.g., both parallel to the dashed line L5), and the surface of the first evaporation zone facing the second chamber 317 (the vertically downward surface) is flush with the surface of each second evaporation zone 315 facing the second chamber 317 (the vertically downward surface) (e.g., both parallel to the dashed line L6). In this way, the first evaporation zone 314 and the second evaporation zone 315 can also be formed on the base plate 318 by extrusion molding. Then, the first flow channel 3141 is machined on the first evaporation zone 314 by turning (or other machining methods), and the second flow channel 3151 is machined on the second evaporation zone 315.

[0143] In order to better transfer the heat on the first power device 21 to the first substrate 31, the first power device 21 can be fixedly connected to the first substrate 31, so that the first power device 21 and the first substrate 31 are in full contact, reducing the possibility of gaps between the contact surfaces of the first power device 21 and the first substrate 31. For example, Figure 18 illustrates a fixed connection method.

[0144] Referring to Figure 18, the first power device 21 can be fixedly connected to the first substrate 31 by bolts 211. The circuit board 2 has through holes 22 for the head 2111 of the bolt 211 to pass through. The shank 2112 of the bolt 211 passes through the first power device 21 and is threadedly connected to the first substrate 31 (the first substrate 31 has threaded holes 3181 for threaded connection of the bolt 211). The head 2111 of the bolt 211 abuts against the surface of the first power device 21 facing away from the first substrate 31, allowing the first power device 21 to fit snugly against the first substrate 31, thus improving the heat dissipation of the first power device 21. Multiple bolts 211 can be provided, and multiple through holes 22 can also be provided.

[0145] In the example shown in Figure 18, the shank 2112 of the bolt 211 does not extend into or pass through the first gas-liquid channel 310. Furthermore, the head 2111 of the bolt 211 abuts against the first power device 21 rather than the circuit board 2, reducing the possibility of damage to the circuit board 2 during bolt installation and minimizing the impact on the circuit board 2 when connecting the first power device 21 and the first substrate 31.

[0146] Referring to FIG18, it can be understood that the threaded hole 3181 for the bolt 211 to be threaded is a blind hole, and the threaded hole 3181 is formed on the surface of the first substrate 31 facing the first power device 21. For example, when the first substrate 31 includes a base plate 318 and a cover plate 319 (refer to FIG17 for further details), the threaded hole 3181 is formed on the surface of the base plate 318 away from the cover plate 319. In addition, FIG19 shows an exemplary structure of another threaded hole 3181. Referring to FIG19, the first substrate 31 includes a base plate 318 and a cover plate 319. A boss 3191 is provided on the cover plate 319, and a threaded hole 3181 is formed in the boss 3191. The boss 3191 extends toward the first power device 21 and passes through the base plate 318, so that the threaded hole 3181 is exposed. The bolt 211 passes through the first power device 21 and is threadedly connected to the threaded hole 3181 in the boss 3191. If the threaded hole 3181 in Figure 19 is adopted, since the boss 3191 needs to pass through the base plate 318, the boss 3191 needs to be welded to the base plate 318 for sealing (for example, welding is required at the arrow X2) to reduce the possibility of cooling fluid leakage in the first gas-liquid channel 310. However, by adopting the threaded hole 3181 in Figures 17 and 18, the threaded hole 3181 is provided as a blind hole on the surface of the first substrate 31 facing the first power device 21, which can reduce the sealing weld of the bolt 211 circumferentially.

[0147] Furthermore, in some examples, referring to Figures 18 and 19, the first substrate 31 extends vertically and protrudes beyond the first heat sink 32 (protruding below the first heat sink 32). The first power device 21 makes thermal contact with the portion of the first substrate 31 protruding from the first heat sink 32, with a portion of the first power device 21 extending below the first heat sink 32 and another portion facing the first heat sink 32 in the first direction. That is, the first heat sink 32 and the first power device 21 have an overlapping area in the first direction. This causes a portion of the bolts 211 to face the first heat sink 32 in the first direction, for example, the bolts 211 circled by the dashed lines in Figures 18 and 19. In some examples, the positions of such bolts 211 and the corresponding threaded holes 3181 can be adjusted to reduce the thickness of the first substrate 31. For example, Figure 20 illustrates the structure of such a threaded hole 3181. Referring to Figure 20, the first heat dissipation part 32 includes a plurality of first condenser tubes 321 spaced apart along the second direction. Each first condenser tube 321 passes through the side wall of the first substrate 31 away from the first power device 21 and extends into the first gas-liquid channel 310. If the area of ​​the first substrate 31 where the threaded hole 3181 is provided protrudes into the first gas-liquid channel 310 on the side away from the first power device 21 (forming a boss protruding into the first gas-liquid channel 310), then the position of the threaded hole 3181 (that is, the position of the bolt 211) can be directly opposite the area between two adjacent first condenser tubes 321 in the first direction (e.g., the area where the fin 34 is located). In this way, the part of the first condenser tube 321 extending into the first gas-liquid channel 310 and the bolt 211 can be staggered, ensuring that the cooling medium can flow smoothly in the first gas-liquid channel 310 while reducing the thickness of the first substrate 31.

[0148] Since the circuit board 2 is located inside the power cavity 111, when the power conversion device 100 is operating, the circuit board 2 and the components thereon generate significant heat, resulting in a high temperature inside the power cavity 111. Therefore, it is necessary to dissipate heat from the power cavity 111, or in other words, to dissipate heat from the circuit board 2 and the components thereon (e.g., electronic component 25 in the example of Figure 2). Referring back to Figures 3 and 4, the power conversion device 100 may further include a first heat exchanger 4, which is used to transfer heat from the power cavity 111 to the heat dissipation cavity 112 to dissipate heat from the electronic component 25.

[0149] In one example, a first heat exchanger 4 is disposed within a heat dissipation cavity 112, and the heat exchange channel within the first heat exchanger 4 is connected to a power cavity 111. A first heat exchange channel (located within the first heat exchanger 4, therefore not shown in the accompanying drawings) is formed within the first heat exchanger 4. The first heat exchange channel is isolated from the heat dissipation cavity 112 and has an inlet and an outlet (obscured, therefore not shown in the accompanying drawings) on the first heat exchanger 4. Both the inlet and outlet of the first heat exchange channel are connected to the power cavity 111. For example, the inlet and outlet of the first heat exchange channel are respectively connected to corresponding mounting ports 114 on the partition 11 to achieve communication between the first heat exchange channel inside the first heat exchanger 4 and the power cavity 111.

[0150] The first heat exchanger 4 allows hot air from the power cavity 111 to enter its first heat exchange channel, where it exchanges heat with the air in the heat dissipation cavity 112. The heat exchanger 3 connects to the outside environment through heat dissipation holes 121, enabling heat exchange between the air in the heat dissipation cavity 112 and the outside environment. In this way, the first heat exchanger 4 can efficiently dissipate heat within the heat dissipation cavity 112, reducing the temperature inside the power cavity 111 and allowing the power conversion device 100 to operate stably.

[0151] Referring to Figure 4, the first heat exchanger 4 includes a finned heat exchanger. For example, the first heat exchanger 4 includes a plurality of first flat heat dissipation tubes 41 and a plurality of first heat dissipation fins 42 (e.g., a fin-like structure). The plurality of first flat heat dissipation tubes 41 are spaced apart along a first direction, and a plurality of first heat dissipation fins 42 are disposed between two adjacent first flat heat dissipation tubes 41. The internal space of the plurality of first flat heat dissipation tubes 41 forms the first heat exchange channel of the first heat exchanger 4. In other examples, the first heat exchange channel in the first heat exchanger 4 includes a channel similar to an "S" shape or a serpentine shape.

[0152] Referring to Figures 3 and 4, the first heat exchanger 4 is at least partially located between the portion of the first substrate 31 protruding from the first heat dissipation portion 32 and the first heat dissipation portion 32. Alternatively, the portion of the first substrate 31 protruding below the first heat dissipation portion 32 and the first heat dissipation portion 32 form a receiving space 33, and the first heat exchanger 4 is at least partially disposed within the receiving space 33. For example, the first heat exchanger 4 is located on the side of the first substrate 31 facing away from the partition 11, and the first heat exchanger 4 is located below the first heat dissipation portion 32. Installing the first heat exchanger 4 within the receiving space 33, so that the first heat exchanger 4 spans the first substrate 31 and overlaps with the portion of the first substrate 31 protruding from the first heat dissipation portion 32 in a first direction, allows for a more compact installation of the heat dissipation radiator 3 and the first heat exchanger 4, reducing the space occupied by the heat dissipation cavity 112.

[0153] In some other examples, referring to Figure 21, Figure 21 exemplarily shows another configuration of the first heat exchanger 4, which is located inside the power cavity 111. The first heat exchange channel inside the first heat exchanger 4 is isolated from the power cavity 111. The first heat exchange channel has an inlet and an outlet provided on the first heat exchanger 4. The inlet and outlet of the first heat exchange channel are respectively connected to the heat dissipation cavity 112 through corresponding mounting ports 114 on the partition 11.

[0154] With the above design, the air in the heat dissipation cavity 112 can enter the first heat exchange channel of the first heat exchanger 4, and then exchange heat with the hot air in the power cavity 111 through the first heat exchanger 4, while the heat dissipation cavity 112 is open for ventilation. In this way, outside air can continuously enter the first heat exchange channel of the first heat exchanger 4, reducing the temperature in the power cavity 111 and enabling the power conversion device 100 to operate stably.

[0155] In some other examples, referring to FIG22, FIG22 exemplarily shows another arrangement of the first heat exchanger 4, which is located in the heat dissipation cavity 112. The first heat exchanger 4 includes a heat-conducting plate 43 and a plurality of heat dissipation fins 44 connected to each other. The heat-conducting plate 43 is thermally bonded to the first substrate 31. The plurality of heat dissipation fins 44 are fixed along the second direction on the side of the heat-conducting plate 43 away from the first substrate 31. A first fan 8 is provided in the heat dissipation cavity 112, which is used to generate airflow through the heat dissipation fins 44.

[0156] The temperature of electronic device 25 increases, which in turn increases the temperature of power cavity 111. The heat inside power cavity 111 is transferred to heat-conducting plate 43 through first substrate 31, and then heat-conducting plate 43 transfers the heat to heat dissipation fins 44. First fan 8 blows air towards heat dissipation fins 44, and heat dissipation cavity 112 is open for ventilation, which can blow the heat on heat dissipation fins 44 to the outside of heat dissipation cavity 112 (or outside of protective cover 12), that is, to the outside. The rotation of first fan 8 can dissipate heat from heat dissipation fins 44, which is to indirectly dissipate heat from electronic device 25 in power cavity 111.

[0157] In the example where the first substrate 31 protrudes below the first heat dissipation portion 32, referring to FIG22, the heat-conducting plate 43 is thermally bonded to the portion of the first substrate 31 protruding from the first heat dissipation portion 32, and the heat dissipation fins 44 are located below the first heat dissipation portion 32. The first substrate 31 extends downward and forms a space with the first heat dissipation portion 32 (which may be the receiving space 33 in FIG4). Installing the first heat exchanger 4 in this space allows for a more compact installation of the heat dissipation radiator 3 and the first heat exchanger 4, reducing the space occupied by the heat dissipation cavity 112. Furthermore, the first power device 21 contacts the protruding portion of the first substrate 31 (refer to FIG5), and the heat-conducting plate 43, in contact with the protruding portion of the first substrate 31 and in conjunction with the heat dissipation fins 44, can also assist in dissipating heat for the first power device 21.

[0158] In some examples, referring to Figure 22, the power device also includes components that generate significant heat, such as inductor 24 (different from the inductors in the aforementioned plurality of electronic components 25). These components, such as inductor 24, can be housed within the heat dissipation cavity 112 and fixedly connected to the partition 11, which facilitates heat dissipation. The inductor 24 and other components generating significant heat can be electrically connected to the circuit board 2 via wires passing through the partition 11. To make efficient use of the space within the heat dissipation cavity 112, inductor 24 can be positioned above the first substrate 31.

[0159] In addition, to facilitate heat dissipation, in one example, referring back to Figures 1 and 2, the power conversion device 100 also includes a first fan 8. The heat dissipation hole 121 includes an air inlet 1211 and an air outlet 1212. One of the air inlet 1211 and the air outlet 1212 is located below the heat sink 3, and the other is located above the heat sink 3. That is, the air inlet 1211 and the air outlet 1212 are located on the upper and lower sides of the heat sink 3, respectively. The first fan 8 is used to drive the air entering through the air inlet 1211 to be discharged through the air outlet 1212. Under the action of the first fan 8, the air outside the protective cover 12 enters through the air inlet 1211, passes through the heat sink 3, and is discharged through the air outlet 1212, so that the outside air can pass through the heat sink 3 fully, thereby improving the heat dissipation effect of the heat sink 3.

[0160] For example, the air inlet 1211 is located below the radiator 3, and the air outlet 1212 is located above the radiator 3. The air temperature in the heat dissipation cavity 112 after heat exchange with the heat exchanger and radiator 3 is relatively high. Since hot air is less dense than cold air, the same volume of hot air is lighter than cold air, causing it to rise. Therefore, placing the air inlet 1211 at the bottom and the air outlet 1212 at the top better conforms to the airflow pattern in the heat dissipation cavity 112, resulting in better heat dissipation.

[0161] Multiple air inlets 1211 and air outlets 1212 can be provided. In some examples, the air inlets 1211 and air outlets 1212 have the same shape and size.

[0162] Figure 23 illustrates an exemplary internal structure of another power conversion device 100, and Figure 24 illustrates an exemplary exploded view of a portion of the power conversion device 100 in Figure 23. The structures of the housing 1 and the protective cover 12 in this example can be the same as those shown in Figure 1. In the examples shown in Figures 23 and 24, the heat sink 3 includes a first substrate 31 and a first heat dissipation section 32, as well as a second substrate 36 and a second heat dissipation section 37. The second substrate 36 is distributed and fixedly connected to the first substrate 31 in a vertical direction.

[0163] Figure 25 exemplarily illustrates the internal chambers of the second substrate 36 and the second heat dissipation section 37. Referring to Figures 24 and 25, a third gas-liquid channel 360 is provided within the second substrate 36, and a cooling medium for gas-liquid conversion is provided within the third gas-liquid channel 360. A fourth gas-liquid channel 370 is provided within the second heat dissipation section 37, which communicates with the third gas-liquid channel 360. The third gas-liquid channel 360 is isolated from the first gas-liquid channel 310, meaning that the second substrate 36 and the first substrate 31 are not in communication. Furthermore, the second heat dissipation section 37 is located on the side of the second substrate 36 facing away from the partition plate 11.

[0164] Referring to Figure 24, in addition to the first power device 21, a second power device 23 is also provided on the side of the circuit board 2 facing the opening 113. In some examples, the second power device 23 can also constitute the power conversion circuit of the power conversion device 100 to convert the DC power input to the power conversion device 100. For example, the second power device 23 includes a chip. In other examples, the second power device 23 can also be a power device on the circuit board 2 that plays other roles. The second power device 23 is in contact with the second substrate 36. When there are many power devices on the circuit board 2 that require heat dissipation, and there is a height difference between different power devices (the first power device 21 and the second power device 23), the second substrate 36 and the second heat dissipation part 37 can better dissipate heat for the second power device 23, reducing the possibility that the normal operation of the power conversion device 100 will be affected by the excessive heat generated by the second power device 23.

[0165] After the first substrate 31 and the second substrate 36 are connected, the opening 113 is sealed, reducing the possibility of air in the heat dissipation cavity 112 entering the power cavity 111. In addition, the power cavity 111 (e.g., the interior of the housing 1 in FIG. 23) and the heat dissipation cavity 112 are distributed along the first direction, and the first substrate 31 and the second substrate 36 are distributed along the vertical direction. This can reduce the size of the heat sink 3 in the first direction, thereby reducing the size of the heat dissipation cavity 112 in the first direction, and thus reducing the size of the power conversion device 100 in the first direction.

[0166] Referring to Figure 25, the second substrate 36 protrudes downwards from the second heat sink 37, and the second power device 23 is partially located below the second heat sink 37. This reduces the overlap between the second heat sink 37 and the second power device 23, allowing more of the second heat sink 37 to exchange heat with the air in the heat dissipation cavity 112, thus improving heat dissipation. In other examples, the second power device 23 is completely located below the second heat sink 37; that is, the second power device 23 and the second heat sink 37 are located on opposite sides of the second substrate 36, and there is a vertical distance between them.

[0167] In some examples, referring to FIG25, the structure of the second substrate 36 may be the same as that of the first substrate 31. In other examples, the second substrate 36 is a different structure that can perform the same function as the first substrate 31. Furthermore, the dimensions of the first substrate 31 and the second substrate 36 may be the same or different; this application does not impose specific limitations in this regard. In the examples shown in FIGS. 23 to 25, the first substrate 31 is located above the second substrate 36; in this example, the first heat sink 32 is also located above the second heat sink 37. In other examples, the first substrate 31 may also be located below the second substrate 36; in this example, the first heat sink 32 is also located below the second heat sink 37.

[0168] Referring to Figure 24, the second heat dissipation part 37 may include a plurality of spaced second condenser tubes 371, and a plurality of fins 34 are provided between two adjacent second condenser tubes 371 (similar to the structure of the first heat dissipation part 32 in Figure 6). In the first heat dissipation part 32 and the second heat dissipation part 37, the number of fins 34 provided in the one closer to the air inlet 1211 is less than the number of fins 34 provided in the one farther from the air inlet 1211.

[0169] Since the air at the air inlet 1211 has just entered the heat dissipation cavity 112 from the outside, the air temperature is lower the closer it is to the air inlet 1211. When the air passes through the one of the first heat dissipation section 32 and the second heat dissipation section 37 that is closer to the air inlet 1211, heat exchange will occur, and the air temperature will rise after heat exchange. That is, in the heat dissipation cavity 112, the closer the air is to the air outlet 1212, the higher the air temperature. The one of the first heat dissipation section 32 and the second heat dissipation section 37 that is closer to the air inlet 1211 has sparser fins 34, so that a large amount of air can pass through and more air is blown to the one that is farther away. The one that is farther away from the air inlet 1211 has denser secondary fins 34 to enhance the heat dissipation capacity, so that the vertically arranged first heat dissipation section 32 and second heat dissipation section 37 can dissipate heat evenly.

[0170] Referring to Figures 23 and 24, taking the example where the air inlet 1211 is located below the radiator 3, if the first heat dissipation part 32 is located above the second heat dissipation part 37, then the fins 34 of the second heat dissipation part 37 are more sparse than those of the first heat dissipation part 32; that is, the fins 34 of the first heat dissipation part 32 are more dense than those of the second heat dissipation part 37. In the example where the air inlet 1211 is located above the radiator 3, if the first heat dissipation part 32 is located above the second heat dissipation part 37, then the fins 34 of the second heat dissipation part 37 are more dense than those of the first heat dissipation part 32; that is, the fins 34 of the first heat dissipation part 32 are more sparse than those of the second heat dissipation part 37.

[0171] In other examples, referring to Figure 26, which exemplarily illustrates another arrangement of the first heat dissipation section 32 and the second heat dissipation section 37, in this example, the dimension of the first heat dissipation section 32 and the second heat dissipation section 37 closer to the air inlet 1211 in the first direction is smaller than the dimension of the second heat dissipation section farther from the air inlet 1211 in the first direction. That is, the heat dissipation section closer to the air inlet 1211 is shorter in the first direction. By adopting an arrangement of different lengths, more cool air can be blown to the first heat dissipation section 32 and the second heat dissipation section 37 farther from the air inlet 1211, thereby enhancing the heat dissipation capacity of the radiator 3 and enabling the vertically arranged first heat dissipation section 32 and the second heat dissipation section 37 to dissipate heat evenly.

[0172] In the example shown in Figure 26, fins 34 may not be provided, or fins 34 may be provided in the first heat dissipation part 32 and the second heat dissipation part 37. The density of fins 34 in the first heat dissipation part 32 and the second heat dissipation part 37 may be set according to the distance from the air inlet hole 1211, which will not be elaborated here.

[0173] Referring back to Figures 23 and 24, in addition to the first heat exchanger 4, the power conversion device 100 also includes a second heat exchanger 5 disposed within the heat dissipation cavity 112. The second heat exchanger 5 is used to transfer heat from the power cavity 111 to the heat dissipation cavity 112 to dissipate heat from the electronic device 25. For example, a second heat exchange channel (not shown in the figures because it is located within the second heat exchanger 5) is provided within the second heat exchanger 5. The second heat exchange channel communicates with the power cavity 111 (located within the housing 1). The hot air in the power cavity 111 can exchange heat with the air in the heat dissipation cavity 112 through the first heat exchanger 4 and the second heat exchanger 5, further reducing the temperature within the power cavity 111 and enabling the power conversion device 100 to operate stably.

[0174] Referring to Figure 23, since the first substrate 31 protrudes downwards from the first heat dissipation part 32 and the second substrate 36 extends downwards from the second heat dissipation part 37, there is ample space below both the first heat dissipation part 32 and the second heat dissipation part 37. One of the first heat exchanger 4 and the second heat exchanger 5 is disposed between the first heat dissipation part 32 and the second heat dissipation part 37, and the other is located below the one with the lower height of the first heat dissipation part 32 and the second heat dissipation part 37.

[0175] In other words, when the first heat exchanger 4 and the second heat exchanger 5 are installed, the extra space below the first heat dissipation part 32 and the second heat dissipation part 37 is fully utilized, making the installation of the radiator 3, the first heat exchanger 4 and the second heat exchanger 5 more compact. The space in the vertical direction of the heat dissipation cavity 112 is fully utilized, reducing the size of the power conversion device 100 in the first direction.

[0176] For example, in the example shown in Figure 23, the first heat dissipation section 32 is located above the second heat dissipation section 37, and the receiving space 33 is located between the first heat dissipation section 32 and the second heat dissipation section 37 (see Figure 24 for reference). The first heat exchanger 4 is disposed between the first heat dissipation section 32 and the second heat dissipation section 37, and the second heat exchanger 5 is disposed below the second heat dissipation section 37. In other examples, the first heat dissipation section 32 is located below the second heat dissipation section 37, and the second heat exchanger 5 is disposed between the first heat dissipation section 32 and the second heat dissipation section 37, and the first heat exchanger 4 is disposed below the first heat dissipation section 32.

[0177] In one example, to facilitate the unified installation of the first heat exchanger 4 and the second heat exchanger 5, the first heat exchanger 4 and the second heat exchanger 5 can be connected. Figure 27 illustrates this structure. Referring to Figure 27, the inlet of the first heat exchange channel in the first heat exchanger 4 and the inlet of the second heat exchange channel in the second heat exchanger 5 are both connected to the first connecting pipe 6. The outlet of the heat exchange channel in the first heat exchanger 4 and the outlet of the heat exchange channel in the second heat exchanger 5 are both connected to the second connecting pipe 7. The first connecting pipe 6 and the second connecting pipe 7 are both connected to the power cavity 111.

[0178] The first heat exchanger 4 and the second heat exchanger 5 are interconnected and fixed together by the first connecting pipe 6 and the second connecting pipe 7, which improves the integration of the first heat exchanger 4 and the second heat exchanger 5. It eliminates the need to install the first heat exchanger 4 and the second heat exchanger 5 separately and connect them to the power cavity 111 separately, which is beneficial for the unified assembly and disassembly of the first heat exchanger 4 and the second heat exchanger 5 in the heat dissipation cavity 112.

[0179] The first connecting pipe 6 is provided with a heat exchange inlet 61, and the second connecting pipe 7 is provided with a heat exchange outlet 71. The heat exchange inlet 61 and the heat exchange outlet 71 are respectively connected to the corresponding mounting ports 114 on the partition plate 11 (refer to Figure 24) to realize the connection between the heat exchange channels inside the first heat exchanger 4 and the heat exchange channels inside the second heat exchanger 5 and the power cavity 111. The hot air in the power cavity 111 enters the first heat exchanger 4 and the second heat exchanger 5 through the first connecting pipe 6. After the hot air in the first heat exchanger 4 and the second heat exchanger 5 exchanges heat with the air in the heat dissipation cavity 112, it enters the second connecting pipe 7 and then enters the power cavity 111.

[0180] In one example, referring to FIG23, the first heat exchange channel of the first heat exchanger 4 and the second heat exchange channel of the second heat exchanger 5 both extend along the second direction. The first connecting pipe 6 and the second connecting pipe 7 are respectively located on different sides of the lower of the first heat dissipation section 32 and the second heat dissipation section 37 in the second direction. For example, in the example shown in FIG23, the first heat dissipation section 32 is located above the second heat dissipation section 37, and the first connecting pipe 6 and the second connecting pipe 7 are located on different sides of the second heat dissipation section 37 in the second direction.

[0181] With the above design, the first heat dissipation part 32, the first heat exchanger 4, the second heat dissipation part 37 and the second heat exchanger 5 are alternately distributed. The space above and below the lower one of the first heat dissipation part 32 and the second heat dissipation part 37 is utilized by the first heat exchanger 4 and the second heat exchanger 5, respectively. The space on both sides of the lower one of the first heat dissipation part 32 and the second heat dissipation part 37 is utilized by the first connecting pipe 6 and the second connecting pipe 7, respectively. This can make fuller use of the space of the heat dissipation cavity 112 and reduce the volume of the power conversion device 100.

[0182] In one example, referring to Figure 27, the second heat exchanger 5 includes a finned heat exchanger. For example, the second heat exchanger 5 includes a plurality of second flat heat dissipation tubes 51 and a plurality of second heat dissipation fins 52 (e.g., a fin-like structure). The plurality of second flat heat dissipation tubes 51 are spaced apart along a first direction, and a plurality of second heat dissipation fins 52 are disposed between each pair of adjacent second flat heat dissipation tubes 51. The internal space of the plurality of second flat heat dissipation tubes 51 forms the second heat exchange channel of the second heat exchanger 5. In other examples, the second heat exchange channel in the second heat exchanger 5 includes an "S"-shaped channel or a serpentine channel.

[0183] In some examples, to facilitate the flow of air within the power cavity 111 in the first heat exchanger 4 and the second heat exchanger 5, a drive fan (not shown in the figures) can be provided within the power cavity 111 to drive the airflow.

[0184] In other examples, the structure and location of the first heat exchanger 4 can be adjusted as needed. For example, Figure 28 exemplarily shows the internal structure of another power conversion device 100, and Figure 29 exemplarily shows an exploded view of a portion of the power conversion device 100 in Figure 28. Referring to Figures 28 and 29, a through-hole 115 is provided on the partition 11. The first heat exchanger 4 includes a heat-conducting plate 43 (e.g., a metal plate) and multiple heat dissipation fins 44 (e.g., metal sheets). The multiple heat dissipation fins 44 include multiple first heat dissipation fins 441 and multiple second heat dissipation fins 442. The heat-conducting plate 43 is located at the through-hole 115, and the first heat dissipation fins 441 and the second heat dissipation fins 442 are respectively fixed to different surfaces of the heat-conducting plate 43. Furthermore, the multiple first heat dissipation fins 441 are arranged at intervals along a second direction, and the multiple second heat dissipation fins 442 are arranged at intervals along a second direction. The heat-conducting plate 43 and the first heat dissipation fin 441 are located inside the heat dissipation cavity 112, and the second heat dissipation fin 442 extends into the power cavity 111 through the through-hole 115.

[0185] In some other examples, Figure 30 exemplarily illustrates the internal structure of another power conversion device 100, in which a heat-conducting plate 43 and a second heat dissipation fin 442 are located in a power cavity 111, and a first heat dissipation fin 441 extends into the heat dissipation cavity 112 through a through-hole 115.

[0186] Referring to any one of Figures 28 to 30, a second fan 9 is provided inside the heat dissipation cavity 112. The second fan 9 is used to generate airflow through the first heat dissipation fin 441. By providing the second fan 9, the airflow in the power cavity 111 is made so that the heat in the power cavity 111 can be continuously conducted to the second heat dissipation fin 422 and transferred outward through the second heat dissipation fin 422.

[0187] Furthermore, referring to any of Figures 28 to 30, a first fan 8 may also be provided inside the heat dissipation cavity 112. The first fan 8 is used to generate airflow through the first heat dissipation fins 441. After the temperature of the power cavity 111 rises, the heat inside the power cavity 111 will be transferred to the heat conduction plate 43 through the second heat dissipation fins 442, and then transferred to the first heat dissipation fins 441 through the heat conduction plate 43. The first fan 8 blows air towards the first heat dissipation fins 441, which can blow the heat on the first heat dissipation fins 441 out of the heat dissipation cavity 112, that is, to the outside, thereby continuously dissipating heat from the first heat dissipation fins 441, thus cooling the power cavity 111 and reducing its internal temperature.

[0188] In the case where the first heat exchanger 4 includes a heat-conducting plate 43, a plurality of first heat dissipation fins 441, and a plurality of second heat dissipation fins 442, in the examples shown in Figures 28 to 30, the first heat exchanger 4 and the radiator 3 are arranged in a vertical direction; for example, the first heat exchanger 4 is located below the radiator 3. In some other examples, the first heat exchanger 4 and the radiator 3 may also be arranged in a horizontal direction (e.g., a second direction), wherein Figure 31 exemplarily shows the positions of various first heat exchangers. Referring to Figure 31(a), the first heat exchanger 4 can be disposed on one side of the radiator 3 in the second direction; referring to Figures 31(b) and (c), the radiator 3 is provided with a through-hole 115 on each side in the second direction (the structure of the through-hole 115 is shown in any of Figures 28 to 30), a first heat exchanger 4 is inserted through the through-hole 115 on one side of the radiator 3, and a second heat exchanger 5 is inserted through the through-hole 115 on the other side of the radiator 3 (the structure of the second heat exchanger 5 is the same as that of the first heat exchanger 4), or, a first heat exchanger 4 is inserted through each through-hole 115 (the radiator 3 is provided with a first heat exchanger 4 on each side in the second direction).

[0189] In some examples, the first substrate 31 and the second substrate 36 can be integrally connected, while in other examples, the first substrate 31 and the second substrate 36 can be separately disposed and then fixedly connected to each other (directly fixed or indirectly fixed through other structures).

[0190] In some examples, the first heat exchanger 4 can be separately disposed from the first substrate 31 and then separately installed in the heat dissipation cavity 112. In other examples, the first heat exchanger 4 can be integrally connected to the first substrate 31.

[0191] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A power conversion device, characterized in that, Includes housing, circuit board, radiator, and first heat exchanger. A sealed power cavity is formed inside the housing, and an open and ventilated heat dissipation cavity is formed outside the housing. The housing includes a partition between the power cavity and the heat dissipation cavity. The protection level of the power cavity is higher than that of the heat dissipation cavity. An opening is provided on the partition. A circuit board is disposed inside the power cavity. A first power device is mounted on the side of the circuit board facing the opening. The first power device constitutes the power conversion circuit of the power conversion device to perform power conversion on the DC power input to the power conversion device. The heat sink is disposed in the heat dissipation cavity and includes a first substrate and a first heat dissipation part. The first substrate is disposed at the opening and makes thermal contact with the first power device in the power cavity. The first heat dissipation part extends outward from the first substrate. A first gas-liquid channel is disposed in the first substrate. A second gas-liquid channel is disposed in the first heat dissipation part and communicates with the first gas-liquid channel. A cooling medium for gas-liquid conversion is disposed in the first gas-liquid channel. The included angle between the first gas-liquid channel and the second gas-liquid channel is 90 degrees or greater than 90 degrees and less than 180 degrees. The circuit board has electronic components mounted on the side opposite to where the first power device is mounted. The first heat exchanger is located in the power cavity or the heat dissipation cavity. The first heat exchanger is used to transfer heat from the power cavity to the heat dissipation cavity to dissipate heat from the electronic components.

2. The power conversion device according to claim 1, characterized in that, The first substrate extends vertically and protrudes from the first heat dissipation portion, and the first power device makes thermally conductive contact with the portion of the first substrate protruding from the first heat dissipation portion.

3. The power conversion device according to claim 1 or 2, characterized in that, The first heat exchanger is located within the power cavity, and a first heat exchange channel is formed within the first heat exchanger. The first heat exchange channel is isolated from the power cavity. The first heat exchange channel has an inlet and an outlet disposed on the first heat exchanger, and both the inlet and outlet of the first heat exchange channel are connected to the power conversion device of the heat dissipation cavity; or, the first heat exchanger is located within the heat dissipation cavity, and a first heat exchange channel is formed within the first heat exchanger. The first heat exchange channel is isolated from the heat dissipation cavity. The first heat exchange channel has an inlet and an outlet disposed on the first heat exchanger, and both the inlet and outlet of the first heat exchange channel are connected to the power cavity.

4. The power conversion device according to claim 3, characterized in that, The first substrate extends vertically and protrudes from the first heat dissipation portion, and the first heat exchanger crosses the first substrate and overlaps with the portion of the first substrate that protrudes from the first heat dissipation portion.

5. The power conversion device according to claim 1 or 2, characterized in that, The first heat exchanger is located inside the heat dissipation cavity. The first heat exchanger includes a heat-conducting plate and heat dissipation fins connected to each other. The heat-conducting plate is thermally bonded to the first substrate. A first fan is provided inside the heat dissipation cavity. The first fan is used to generate airflow through the heat dissipation fins.

6. The power conversion device according to claim 5, characterized in that, The first substrate extends vertically and protrudes from the first heat dissipation portion. The heat-conducting plate is thermally bonded to the portion of the first substrate that protrudes from the first heat dissipation portion. The heat dissipation fins are located below the first heat dissipation portion.

7. The power conversion device according to claim 1 or 2, characterized in that, The partition plate is provided with a through opening. The first heat exchanger includes a heat-conducting plate and multiple heat dissipation fins. The multiple heat dissipation fins include a first heat dissipation fin and a second heat dissipation fin. The heat-conducting plate is disposed at the through opening. The first heat dissipation fin and the second heat dissipation fin are respectively fixed to different surfaces of the heat-conducting plate. The heat-conducting plate and the first heat-dissipating fin are located inside the heat dissipation cavity, and the second heat-dissipating fin extends into the power cavity through the through-hole; or, the heat-conducting plate and the second heat-dissipating fin are located inside the power cavity, and the first heat-dissipating fin extends into the heat dissipation cavity through the through-hole. A second fan is provided inside the power cavity to generate airflow through the second heat dissipation fins.

8. The power conversion device according to claim 1, characterized in that, The power cavity and the heat dissipation cavity are distributed along a first direction, which is perpendicular to the vertical direction. The heat sink further includes a second substrate and a second heat dissipation part. The second substrate and the first substrate are distributed along the vertical direction and fixedly connected. The second heat dissipation part extends outward from the second substrate. A third gas-liquid channel is provided in the second substrate. A fourth gas-liquid channel communicating with the third gas-liquid channel is provided in the second heat dissipation part. The third gas-liquid channel is isolated from the first gas-liquid channel. A second power device is provided on the side of the circuit board facing the opening. The second power device is in contact with the second substrate in the heat dissipation cavity. A cooling medium for gas-liquid conversion is provided in the third gas-liquid channel.

9. The power conversion device according to claim 8, characterized in that, The power conversion device further includes a second heat exchanger, which is used to transfer heat from the power cavity to the heat dissipation cavity. Both the first heat exchanger and the second heat exchanger are disposed within the heat dissipation cavity. The first heat dissipation part and the second heat dissipation part are distributed in a vertical direction. The first substrate protrudes downward toward the first heat dissipation part, and the second substrate protrudes downward toward the second heat dissipation part. One of the first heat exchanger and the second heat exchanger is located between the first heat dissipation part and the second heat dissipation part, and the other is located below the one with the lower height of the first heat dissipation part and the second heat dissipation part.

10. The power conversion device according to claim 9, characterized in that, A first heat exchange channel is formed in the first heat exchanger, and a second heat exchange channel is formed in the second heat exchanger. The inlet of the first heat exchange channel and the inlet of the second heat exchange channel are both connected to a first connecting pipe. The outlet of the first heat exchange channel and the outlet of the heat exchange channel are both connected to a second connecting pipe. The first connecting pipe and the second connecting pipe are both located in the heat dissipation cavity and are both connected to the power cavity.

11. The power conversion device according to claim 10, characterized in that, Both the first heat exchange channel and the second heat exchange channel extend along the second direction. The first connecting pipe and the second connecting pipe are respectively located on different sides of the lower of the first heat dissipation part and the second heat dissipation part in the second direction. The first direction, the second direction, and the vertical direction are perpendicular to each other.

12. The power conversion device according to any one of claims 8-11, characterized in that, The power conversion device also includes a protective cover, the heat dissipation cavity is formed inside the protective cover, the protective cover is provided with heat dissipation holes, the heat dissipation holes include air inlets and air outlets, one of the air inlets and the air outlets is located below the heat sink, and the other is located above the heat sink. A first fan is provided inside the heat dissipation cavity, and the first fan is used to drive the air entering through the air inlets to be discharged from the air outlets.

13. The power conversion device according to claim 12, characterized in that, The first heat dissipation section includes a plurality of spaced-apart first condenser tubes, and the second heat dissipation section includes a plurality of spaced-apart second condenser tubes. Multiple fins are provided between adjacent first condenser tubes and between adjacent second condenser tubes. In the first heat dissipation section and the second heat dissipation section, the number of fins provided in the section closer to the air inlet is less than the number of fins provided in the section farther from the air inlet.

14. The power conversion device according to claim 12 or 13, characterized in that, In the first heat dissipation part and the second heat dissipation part, the dimension of the one closer to the air inlet in the first direction is smaller than the dimension of the one farther from the air inlet in the first direction.

15. The power conversion device according to any one of claims 1-14, characterized in that, The angle between the first gas-liquid channel and the second gas-liquid channel is greater than 90 degrees and less than or equal to 160 degrees.

16. The power conversion device according to any one of claims 1-15, characterized in that, The first power device is fixedly connected to the first substrate by bolts. The circuit board is provided with a through hole for the head of the bolt to pass through. The shank of the bolt passes through the first power device and is threadedly connected to the first substrate. The head of the bolt abuts against the surface of the first power device that is away from the first substrate.

17. The power conversion device according to any one of claims 1-16, characterized in that, The inner wall surface of the first substrate forming the first gas-liquid channel includes a first wall surface and a second wall surface. The first wall surface and the second wall surface are disposed opposite to each other in the thickness direction of the first substrate. A plurality of support members are disposed between the first wall surface and the second wall surface. One end of each support member is connected to or abuts against the first wall surface, and the other end is connected to or abuts against the second wall surface.

18. The power conversion device according to claim 17, characterized in that, The first substrate includes a base plate and a cover plate arranged along a first direction. The base plate is connected to the first power device. The cover plate is located on the side of the base plate away from the first power device. The edge of the cover plate is fixedly connected to the edge of the base plate. The cover plate bulges towards the side away from the base plate. The first gas-liquid channel is located between the cover plate and the base plate. One end of each support member is integrally connected to the base plate, and the other end is connected to or abuts against the cover plate. The plurality of support members are divided into multiple rows of support groups arranged along the vertical direction. Each row of the support group includes multiple support members arranged along the second direction. The first direction, the second direction and the vertical direction are perpendicular to each other. A flow equalization channel extending along the second direction is formed between two adjacent rows of the support groups, and the flow equalization channel is connected to the second gas-liquid channel; the surfaces of multiple support members in each row of the support groups facing upward along the vertical direction are flush with each other, and the surfaces of multiple support members facing downward along the vertical direction are flush with each other, and the surfaces of each support member facing upward and downward along the vertical direction are parallel.

19. The power conversion device according to any one of claims 1-18, characterized in that, The heat sink further includes a confluence section, which is disposed in the heat dissipation cavity and connected to the end of the first heat dissipation section away from the first substrate. The second gas-liquid channel includes a plurality of sub-channels, and the confluence section is provided with a confluence channel that communicates with different sub-channels in the second gas-liquid channel, so that different sub-channels in the second gas-liquid channel are interconnected.

20. The power conversion device according to claim 19, characterized in that, The radiator also includes a return pipe, which is located below the first heat dissipation part. One end of the return pipe is connected to the first gas-liquid channel, and the other end is connected to the confluence channel.

21. The power conversion device according to claim 19 or 20, characterized in that, The busbar includes a first plate and a second plate, with the edges of the first plate and the second plate fixedly connected. The first plate is connected to the end of the first heat dissipation part away from the first substrate. The second plate is located on the side of the first plate away from the first heat dissipation part and bulges towards the side away from the first plate. The busbar channel is located between the first plate and the second plate. The second plate is provided with multiple concave structures, which are recessed into the confluence channel in a direction close to the first plate, and the multiple concave structures abut against the first plate.

22. The power conversion device according to any one of claims 1-21, characterized in that, The first gas-liquid channel is provided with a first evaporation zone. The side of the first evaporation zone facing the first power device is connected to the inner wall surface of the first substrate. The outer wall surface of the first substrate corresponding to the inner wall surface connected to the first evaporation zone is in contact with the first power device. The first gas-liquid channel includes a first chamber and a second chamber located on both sides of the first evaporation zone in the vertical direction. The first evaporation zone is provided with a plurality of first flow channels connecting the first chamber and the second chamber.

23. The power conversion device according to claim 22, characterized in that, A second evaporation zone is provided on both sides of the first evaporation zone. The distribution direction of the two second evaporation zones is perpendicular to the vertical direction. The second evaporation zone is provided with a plurality of second flow channels connecting the first chamber and the second chamber. The number of second flow channels on each second evaporation zone is less than the number of first flow channels.

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