Power conversion device

Abstract

The embodiment of the utility model provides power conversion equipment, and relates to the technical field of energy. The power conversion equipment comprises a shell, a power module and a radiator, the shell is used for accommodating the power module, and the power module is used for converting direct current from a photovoltaic module or an energy storage battery into alternating current; the radiator is at least partially located in the shell and connected with the power module, the radiator is provided with a heat exchange channel, and the heat exchange channel is used for allowing airflow to pass through or allowing liquid to pass through. The radiator is internally provided with a flow channel for cooling liquid to flow, and the flow channel is closer to the power module than the heat exchange channel. According to the technical scheme, the heat exchange capacity of the radiator can be improved, heat dissipation can be effectively carried out on the power module in an overload scene, and the overload capacity of the power conversion equipment is improved.

Description

Technical Field

[0001] The present application relates to the field of energy technology, and in particular to a power conversion device. Background Art

[0002] When the grid voltage is abnormal, the grid requires power conversion equipment (such as inverters and energy storage converters) to provide a large current to maintain stable operation of the grid. Therefore, the power conversion equipment needs to have a high overload capacity. However, the main factor limiting the overload capacity of the power conversion equipment is the junction temperature of the power module (the general calculation formula for junction temperature is: junction temperature = case temperature + junction-case thermal resistance * loss). Among them, the package shell of the power module is usually cooled by a heat sink. The stronger the heat dissipation capacity of the heat sink, the lower the case temperature (temperature of the package shell) of the power module, and the lower the junction temperature of the power module.

[0003] In related technologies, an air-cooled radiator is used to dissipate heat for the power module. However, the heat dissipation capacity of the radiator of this solution is limited. Especially in overload scenarios, the heat dissipation capacity of the radiator cannot meet the requirements of normal operation of the power module, thereby affecting the operation of the power conversion equipment in overload scenarios. Utility Model Content

[0004] The present application provides a power conversion device that can improve the heat exchange capacity of the radiator, effectively dissipate heat for the power module in an overload scenario, and enhance the overload capacity of the power conversion device.

[0005] To achieve the above objectives, this application adopts the following technical solutions:

[0006] The present application provides a power conversion device for converting direct current from a photovoltaic module or an energy storage battery into alternating current. The power conversion device includes a shell, a power module and a radiator. The shell is used to accommodate the power module; the radiator is at least partially located in the shell and connected to the power module. The radiator has a heat exchange channel, which is used for airflow or liquid. The radiator also has a flow channel for coolant flow, and the flow channel is closer to the power module than the heat exchange channel.

[0007] The radiator can be an air-cooled radiator, which exchanges heat with the air through multiple heat exchange channels to dissipate heat for the power module (or power module); the radiator can also be a liquid-cooled radiator, which dissipates heat for the power module by the flow of liquid in the heat exchange channel. When the power conversion device is in normal operation (for example, the power conversion device is not in an overload scenario), the heat dissipation requirements of the power module can be met through the heat exchange channel of the radiator. When the power conversion device is in an overload scenario, the heat exchange capacity of the radiator can be increased by introducing flowing coolant into the flow channel, that is, by cooperating with the flow channel and the heat exchange channel, the power module in the overload scenario can be better dissipated, thereby improving the overload capacity of the power conversion device.

[0008] In an optional embodiment, the power conversion device further includes a container and a driving device, the container is used to contain the coolant, the inlet and outlet of the flow channel are both connected to the container, and the driving device is used to drive the coolant to flow between the flow channel and the container.

[0009] When cooling is needed through the coolant in the flow channel, the drive device can be turned on and used to drive the coolant in the container to flow into the flow channel of the radiator. The coolant removes heat from the radiator in the flow channel (part of the heat comes from the power module, and some heat may come from other components on the circuit board) and then returns to the container under the drive of the drive device. The coolant returning to the container from the flow channel of the radiator is at a higher temperature. This part of the coolant cools down in the container and then flows back to the radiator under the drive of the drive device, thus circulating and continuously cooling the power module.

[0010] In an optional embodiment, the driving device is used to drive the coolant to flow when the current value flowing into or out of the power module is greater than or equal to a first threshold.

[0011] When the current flowing into or out of the power module is large enough (for example, the current value is greater than or equal to the first threshold value), the power module generates severe heat, and the temperature of the power module will rise significantly (or will rise significantly), and the driving device starts and drives the coolant to flow between the flow channel and the container to dissipate heat for the power module. When the current flowing into or out of the power module is reduced to a certain level (for example, the current value is less than the first threshold value), the heat generation of the power module will not be too serious, and the temperature will also drop. At this time, the driving device can stop running, that is, the driving device no longer drives the coolant in the flow channel to circulate, and the power module can meet the heat dissipation requirements only through the heat exchange channel of the radiator. The overload scenario has the characteristics of large loss and short duration. The present application sets the start and stop conditions of the driving device so that the first power device operates only when there is a demand, thereby improving the transient heat exchange capacity of the radiator, effectively dealing with the problem of severe heat generation of the power module in the overload scenario, and saving energy and reducing consumption, thereby economically improving the overload capacity of the power conversion equipment.

[0012] In an optional embodiment, the driving device is used to drive the coolant to flow when the temperature value of the power module is greater than or equal to a second threshold.

[0013] When the temperature of the power module is high (for example, the temperature value is greater than or equal to the second threshold), the drive device starts and drives the coolant to flow between the flow channel and the container to dissipate heat for the power module. After the temperature of the power module drops (for example, the temperature value is less than the second threshold), the drive device stops running. In other words, the drive device no longer drives the coolant in the flow channel to circulate, and the power module can meet the heat dissipation requirements only through the heat exchange channel of the radiator. By setting the start-up conditions of the drive device, the first power device is only operated when required, which improves the transient heat exchange capacity of the radiator and more economically improves the overload capacity of the power conversion equipment.

[0014] In an optional embodiment, the shell has an air inlet, the container is fixed in the shell and located at the air inlet, and the container is closer to the air inlet than the radiator.

[0015] The radiator is connected to the power module (heat source), which means that the radiator is close to the power module. The area around the radiator is easily affected by the temperature of the power module. The container is closer to the air inlet than the radiator, which can keep the container away from the heat source and closer to the air inlet. When the container is located at the air inlet, the air entering the housing from the air inlet can exchange heat with the container, cooling the coolant entering the container (the coolant has just absorbed some of the heat from the power module) at a higher temperature, so that the coolant in the container can be kept as low as possible. In this way, the coolant in the container can still effectively dissipate heat for the power module after re-entering the flow channel, which is conducive to the recycling of the coolant. In addition, the flow channel is closer to the power module than the heat exchange channel, so the low temperature requirement of the coolant in the flow channel is higher. Since the container is closer to the air inlet than the radiator, the cooling speed and cooling effect inside the container are better than those of the radiator. The coolant can be cooled better in the container. After entering the flow channel, the coolant in the container can take away more heat and quickly dissipate heat from the power module.

[0016] In an optional embodiment, the shell has at least two mutually separated accommodating cavities inside, and the power module and the container are respectively located in different accommodating cavities.

[0017] When the container and the power module are located in different cavities in the shell, the heat of the power module has little effect on the temperature of the container, so that the coolant flowing into the container can be cooled quickly, which is also conducive to the recycling of the coolant, so that the coolant can dissipate heat for the power module more efficiently.

[0018] In an optional embodiment, the flow channel and the power module overlap in the thickness direction of the power module.

[0019] The power module generates serious heat and is the main heat source in the power conversion equipment. The flow channel and the power module overlap in the thickness direction of the power module, so that the flow path of the coolant in the flow channel can pass through the location of the power module. In this way, the coolant in the flow channel can take away more heat from the power module, which is beneficial to the heat dissipation of the power module.

[0020] In an optional embodiment, the power module includes a substrate, a die and a packaging shell, the packaging shell is used to accommodate the substrate and the die, the die is fixed on the substrate, the packaging shell is connected to the heat sink, and the flow channel and the die overlap in the thickness direction of the substrate.

[0021] In the case where the power module includes a bare chip, the location of the bare chip is an area where the power module generates more serious heat, and the flow channel and the bare chip overlap in the thickness direction of the substrate. That is, the coolant in the flow channel will pass through the location of the bare chip in the power module during the flow process, and take away as much heat as possible around the bare chip, thereby dissipating heat for the bare chip in a targeted manner, making the heat dissipation efficiency of the radiator of the present application higher and the heat dissipation effect better.

[0022] In an optional embodiment, the radiator includes a heat sink and multiple fins, the flow channel is located in the heat sink, the heat sink is connected to the power module, the multiple fins are fixed on the side of the heat sink facing away from the power module, and the heat exchange channel includes the gap between two adjacent fins.

[0023] In the case of an air-cooled radiator, air flows through the gaps between adjacent fins, that is, through the heat exchange channel. The heat on the power module is transferred to the heat sink. Then, through the multiple fins on the heat sink, heat is exchanged with the air in the heat exchange channel, achieving air cooling of the power module. In overload scenarios, the coolant in the flow channel and the air in the heat exchange channel cooperate to dissipate heat from the power module. In other words, the power module is cooled by both air cooling and liquid cooling, improving the heat exchange capacity of the radiator, making the heat dissipation effect of the radiator better, effectively dissipating heat for the power module, and improving the overload capacity of the power conversion equipment.

[0024] In an optional embodiment, the ratio of the cross-sectional area of ​​the flow channel to the cross-sectional area of ​​the heat sink is less than or equal to 0.2, and the cross-sectional areas of the flow channel and the heat sink are parallel to each other and to the thickness direction of the power module.

[0025] The cross-sectional area of ​​the flow channel is small. When no coolant flows through the flow channel, the heat dissipation effect of the radiator will not be greatly affected. Air cooling can still play an important heat dissipation role, reducing the impact of setting the flow channel on the air cooling performance of the radiator.

[0026] In an optional embodiment, the heat exchange channel is located in the radiator and is used for liquid to pass through, and the volume of the heat exchange channel is greater than the volume of the flow channel.

[0027] In the case of a liquid-cooled radiator, the liquid will flow through the heat exchange channel and remove the heat from the power module, achieving liquid cooling of the power module. In an overload scenario, the coolant in the flow channel and the liquid in the heat exchange channel cooperate with each other to dissipate heat for the power module. In other words, through dual liquid cooling, the heat exchange capacity of the radiator is improved, making the liquid cooling effect of the radiator better. In addition, the volume of the heat exchange channel is larger. When there is no coolant flowing in the flow channel, the liquid in the heat exchange channel can also meet the heat dissipation requirements of the power module.

[0028] In an optional embodiment, the power conversion device further includes a container and a driving component, the container is used to accommodate liquid, the inlet and outlet of the heat exchange channel are both connected to the container, and the driving component is used to drive the liquid to flow between the heat exchange channel and the container.

[0029] The driving element drives the liquid in the container to flow into the heat exchange channel of the radiator. In this channel, the liquid removes heat from the radiator (part of which comes from the power module) and then, driven by the driving element, returns to the container. The liquid returning from the radiator's heat exchange channel to the container is at a higher temperature. This portion of the liquid cools down within the container and, driven by the driving element, flows back into the heat exchange channel of the radiator, continuing the cycle to dissipate heat for the power module.

[0030] In an optional embodiment, the radiator further has a working medium cavity inside, in which there is a cooling medium capable of gas-liquid conversion, and the flow channel is closer to the power module than the working medium cavity.

[0031] When the power module in the power conversion device is seriously heated, the heat on the power module will be transferred to the radiator and heat the cooling medium in the working medium cavity. When the cooling medium in the working medium cavity is heated, at least part of the cooling medium will turn into gas. The gaseous cooling medium exchanges heat with the cold source (for example, liquid or air flowing through the heat exchange channel), so that the gaseous cooling medium quickly dissipates heat and condenses, gradually turning back into liquid cooling medium. This cycle continues to dissipate heat for the power module. This application combines the two-phase conversion heat exchange method with the air cooling function or liquid cooling function of the radiator to further reduce the temperature of the power module and enable the power conversion device to operate stably.

[0032] In an optional embodiment, the power conversion device further includes a flexible layer, and the flexible layer is located between the power module and the heat sink.

[0033] By setting a flexible layer, the surface defects of the radiator and the power module (for example, slight unevenness, processing errors, etc.) can be overcome as much as possible, the dimensional tolerances of the radiator and the power module can be absorbed, and the radiator and the power module can be better connected, which is beneficial to the heat dissipation of the power module. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 A schematic diagram of the structure of a photovoltaic system provided in an embodiment of the present application;

[0035] Figure 2 A schematic structural diagram of a power conversion device provided in an embodiment of the present application;

[0036] Figure 3 A schematic structural diagram of another power conversion device provided in an embodiment of the present application;

[0037] Figure 4 A schematic diagram of the internal structure of a power conversion device provided in an embodiment of the present application;

[0038] Figure 5 A schematic diagram of the structure of a power module provided in an embodiment of the present application;

[0039] Figure 6 A schematic structural diagram of a radiator provided in an embodiment of the present application;

[0040] Figure 7 A schematic diagram of the internal structure of another power conversion device provided in an embodiment of the present application;

[0041] Figure 8 A schematic structural diagram of another radiator provided in an embodiment of the present application;

[0042] Figure 9 A schematic structural diagram of another radiator provided in an embodiment of the present application;

[0043] Figure 10 A schematic structural diagram of a working fluid chamber provided in an embodiment of the present application;

[0044] Figure 11 A schematic structural diagram of a container and a driving device provided in an embodiment of the present application;

[0045] Figure 12 A schematic structural diagram of an air inlet provided in an embodiment of the present application;

[0046] Figure 13 A schematic structural diagram of a receiving cavity provided in an embodiment of the present application;

[0047] Figure 14 A schematic structural diagram of a flow channel provided in an embodiment of the present application;

[0048] Figure 15 A schematic diagram of the structure of another flow channel provided in an embodiment of the present application;

[0049] Figure 16 A schematic structural diagram of a bare chip provided in an embodiment of the present application;

[0050] Figure 17 A diagram showing the positions of a flow channel and a die provided in an embodiment of the present application;

[0051] Figure 18 Another diagram of the positions of flow channels and dies provided in an embodiment of the present application;

[0052] Figure 19 A schematic diagram of a cross section of a heat dissipation plate provided in an embodiment of the present application;

[0053] Figure 20 A schematic diagram of a cross section of a flow channel provided in an embodiment of the present application.

[0054] Reference numerals:

[0055] 100-PV system; 101-power conversion equipment; 102-PV panels; 103-switch box; 104-box substation; 105-grid;

[0056] 1-shell; 11-opening; 12-air inlet; 13-accommodating chamber; 14-frame; 15-power chamber; 16-heat dissipation chamber; 17-partition; 2-radiator; 21-heat exchange channel; 22-heat dissipation plate; 23-fin; 231-gap; 24-working fluid chamber; 25-cooling working fluid; 26-flow channel; 261-sub-flow channel; 27-surface; 3-circuit board; 4-power module; 41-substrate; 42-bare chip; 43-package shell; 5-container; 51-main pipe; 52-branch pipe; 6-driving device; 7-sampler; 8-accommodating member; 81-pipeline; 9-driving member; 10-flexible layer. DETAILED DESCRIPTION

[0057] The technical solutions in the embodiments of the present application will be described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments.

[0058] In the drawings of the embodiments of the present application, physical structures such as components and assemblies are represented by guide lines; hollow structures such as openings, holes, spaces, and cavities are represented by guide lines with arrows.

[0059] The embodiment of the present application provides a power conversion device 101. In one example, the power conversion device 101 may be an inverter. In this example, the power conversion device 101 is used in a photovoltaic system 100. Figure 1 The structure of a photovoltaic system 100 is shown as an example. Figure 1 Photovoltaic modules 102 utilize the photovoltaic effect to directly convert sunlight into electrical energy. PV modules 102 typically include multiple (in this application, "multiple" refers to two or more) solar cells connected in series or parallel to achieve a specified rated output power and voltage. Power conversion equipment 101 (e.g., a photovoltaic inverter) converts the DC power from PV modules 102 into AC power. After passing through a switch box 103 for on / off control, the power is then sent to a box-type substation 104 for voltage transformation and output to a power grid 105 or other loads.

[0060] In another example, the power conversion device 101 may be a power conversion system (PCS). In this example, the power conversion device 101 is used in an energy storage system. The DC source of the power conversion device 101 includes an energy storage battery. The power conversion device 101 is used to convert the DC power from the energy storage battery into AC power and output it to the power grid or other loads. In addition, the energy storage converter can also convert the AC power from the power grid into DC power to charge the energy storage battery.

[0061] Figure 2 The structure of a power conversion device 101 is shown as an example. Figure 2 The power conversion device 101 includes a housing 1 and a heat sink 2. The housing 1 is used to accommodate the internal structures and components of the power conversion device 101. For example, the housing 1 can be a device box, a device shell, or a device cabinet. The housing 1 can be a one-piece shell or a split structure. The shape of the housing 1 can be any suitable shape, and the material of the housing 1 can also be set as required, and this application does not impose specific restrictions on this.

[0062] The radiator 2 is used to dissipate heat for the components inside the housing 1. In an example provided in this application, referring to Figure 2 A portion of the heat sink 2 is located inside the housing 1 and is connected to the device to be cooled, and the other portion extends out of the housing 1 through an opening 11 on the housing 1 .

[0063] In other examples, refer to Figure 3 , Figure 3 The structure of another power conversion device 101 is shown as an example. In this example, the housing 1 may include multiple chambers and structures for separating chambers. For example, the housing 1 includes a power chamber 15, a heat dissipation chamber 16, and a partition 17 located between the power chamber 15 and the heat dissipation chamber 16. The power chamber 15 and the heat dissipation chamber 16 are separated by the partition 17. The power conversion device 101 also includes a circuit board 3, electronic components and other structures. The power chamber 15 is used to accommodate the circuit board 3, electronic components and other structures, and the heat dissipation chamber 16 is used to accommodate the radiator 2 and the fan ( Figure 3 The fan is not shown in the figure), wherein, in this example, the radiator 2 is entirely located in the housing 1, and a portion of the radiator 2 is located in the power cavity 15 to connect to the device to be cooled, and the other portion passes through the partition 17 and extends into the heat dissipation cavity 16.

[0064] The housing 1 protects the internal structure of the power conversion device 101. Figure 4 The internal structure of a power conversion device 101 is shown as an example ( Figure 4 Hidden Figure 2 One of the panels of the middle shell 1), refer to Figure 4The power conversion device 101 further includes a circuit board 3 (e.g., a power board), which may be a printed circuit board (PCB), wherein the circuit board 3 is fixed (e.g., bolted, riveted, clamped, etc.) in the housing 1, and a plurality of components (e.g., inductors, capacitors, etc., not shown in the drawings of this application) are provided on the circuit board 3, which can be Figure 4 As can be seen in the figure, the radiator 2 mainly dissipates heat for one or some devices on the circuit board 3, and these devices are blocked by the radiator 2. In addition, the radiator 2 in the drawings of this application may also only show a part of the radiator 2 itself.

[0065] Figure 5 The device for dissipating heat through the heat sink 2 is shown as an example. Figure 5 The power conversion device 101 further includes a plurality of power modules 4, wherein the power modules 4 are used to convert DC power into AC power. Furthermore, if the power conversion device 101 is an energy storage converter, the power modules 4 can be used to convert DC power into AC power, or to convert AC power into DC power and charge the energy storage battery. Figure 5 Taking one of the power modules 4 as an example, the power module 4 is fixed on the circuit board 3, and the power module 4 is electrically connected to the circuit board 3, and the heat sink 2 is located on the side of the power module 4 away from the circuit board 3 and is connected to the power module 4. It should be noted that the connection here means that the heat sink 2 and the power module 4 at least have a contact relationship, for example, the heat sink 2 and the power module 4 are in direct contact, or thermal contact, or a thermal pad or thermal conductive layer structure is sandwiched between the heat sink 2 and the power module 4; for another example, the heat sink 2 and the power module 4 are fixed to each other (for example, bonded) and there is no relative displacement between the two, or the heat sink 2 and the power module 4 are fixed by other structures (for example, bolts, screws, rivets and other fasteners).

[0066] Regarding the connection between the radiator 2 and the power module 4, Figure 6 An example of a connection through an intermediate structure is shown, referring to Figure 6 The power conversion device 101 also includes a flexible layer 10, such as a silicone grease layer, a thermal conductive adhesive layer, etc. The flexible layer 10 is elastic or flexible (for the flexible layer 10 made of some materials, it is elastic or flexible at least before it solidifies). The flexible layer 10 is sandwiched between the power module 4 and the heat sink 2. Figure 6 , a flexible layer 10 is shown between a power module 4 and the heat sink 2. In some other examples, a plurality of flexible layers 10 may be provided between a power module 4 and the heat sink 2. In some other examples, a flexible layer 10 may be provided between multiple power modules 4 and the heat sink 2.

[0067] By setting the flexible layer 10, the surface defects of the radiator 2 and the power module 4 (for example, slight unevenness, processing errors, etc.) can be overcome as much as possible, and the dimensional tolerances of the radiator 2 and the power module 4 can be absorbed, so that the radiator 2 and the power module 4 can be better connected, which is beneficial for the radiator 2 to dissipate heat from the power module 4.

[0068] The radiator 2 may be any suitable heat dissipation device, wherein, in order to perform heat exchange, the radiator 2 further has a heat exchange channel 21 , wherein the heat exchange channel 21 is used for allowing air flow to pass through, or the heat exchange channel 21 is used for allowing liquid to pass through.

[0069] Regarding the structure of the radiator 2, in one example, refer to Figure 6 The radiator 2 is an air-cooled radiator. It includes a heat sink 22 (or a heat sink substrate) and a plurality of fins 23. The heat sink 22 is connected to the power module 4. The plurality of fins 23 are fixed to the side of the heat sink 22 facing away from the power module 4. The heat exchange channel 21 includes a gap 231 between two adjacent fins 23. That is, two fins 23 have one gap 231, and n fins 23 have n-1 gaps 231. The plurality of gaps 231 together constitute the heat exchange channel 21. Air flows through the gaps 231 between adjacent fins 23, that is, air flows through the heat exchange channel 21. The heat on the power module 4 is transferred to the heat sink 22, and then to the plurality of fins 23 on the heat sink 22. Finally, heat is exchanged with the air in the heat exchange channel 21, achieving air-cooling and heat dissipation of the power module 4.

[0070] In the case where the radiator 2 is an air-cooled radiator, the radiator 2 may not be the above-mentioned fin radiator, but a pin-shaped radiator, wherein the radiator 2 includes a heat sink 22 (or a heat sink substrate) and a plurality of pins (needle-shaped or columnar protruding structures), the plurality of pins being fixed to the surface of the heat sink 22 facing away from the power module 4, the heat exchange channel 21 including the space between adjacent pins, and the power module 4 being connected to the surface of the heat sink 22 facing away from the plurality of pins. In the example where the radiator 2 is an air-cooled radiator, a portion of the radiator 2 may be located within the housing 1, while another portion extends outside the housing 1, or a portion of the radiator 2 may be located within the power cavity of the housing 1, while another portion extends into the heat dissipation cavity of the housing 1.

[0071] In another example, referring to Figure 7 , Figure 7 The structure of another radiator 2 is shown as an example. The radiator 2 is a liquid-cooled radiator. For example, the radiator 2 is a liquid-cooled plate (a plate-shaped or plate-like liquid cooler, which does not limit the thickness of the radiator 2 in this application). The heat exchange channel 21 is located in the radiator 2 and is used for passing liquid (for example, water, cooling medium, etc.). Figure 8The heat exchange channel 21 is shown as an example within the radiator 2. The shape and arrangement of the heat exchange channel 21 within the radiator 2 can be customized as needed. For example, the heat exchange channel 21 can extend in an S-shape or a serpentine shape. The heat exchange channel 21 can also include multiple sub-channels, and the multiple sub-channels can be arranged side by side or in parallel within the radiator 2. This application does not impose specific limitations on this. In the example where the radiator 2 is a liquid-cooled radiator, the radiator 2 can be entirely disposed within the housing 1.

[0072] Reference Figure 7 and Figure 8 The power conversion device 101 further includes a container 8 and a driving member 9. The container 8 may be a liquid storage tank, a liquid storage box, or a liquid storage cabinet, and this application does not impose any restrictions thereto. The container 8 is used to contain liquid. The inlet and outlet of the heat exchange channel 21 are both connected to the container 8 (for example, through corresponding pipes 81). The driving member 9 is connected (for example, through corresponding pipes 81) to the container 8 and the heat exchange channel 21. The driving member 9 is used to drive the liquid to flow between the heat exchange channel 21 and the container 8. The driving member 9 may be a micro water pump or other liquid driving device. The driving member 9 may be disposed in the housing 1, for example, Figure 7 In the illustrated example, in some other examples, the driving member 9 may also be arranged outside the housing 1 .

[0073] The driving member 9 can drive the liquid in the container 8 to flow into the heat exchange channel 21 of the radiator 2. The liquid will remove the heat of the radiator 2 in the heat exchange channel 21 (part of the heat on the radiator 2 comes from the power module 4), and then the liquid will return to the container 8 under the drive of the driving member 9. In the example where the container 8 is arranged in the housing 1, the container 8 can be arranged at the air inlet 12 of the housing 1, or it can be separated from the power module 4 by a partition structure so that the temperature of the environment in which the container 8 is located is lower. Since the temperature of the liquid returning to the container 8 from the heat exchange channel 21 of the radiator 2 is higher, the temperature of the environment in which the container 8 is located is lower, so that the higher temperature liquid can be cooled in the container 8 and then flow back into the heat exchange channel 21 of the radiator 2 under the drive of the driving member 9, thereby continuing to dissipate heat for the power module 4.

[0074] Figure 9 The structure of another radiator 2 is exemplarily shown. In this example, the radiator 2 is a two-phase working medium radiator (or called a two-phase working medium heat exchanger), and the radiator 2 further has a working medium cavity 24 (not shown). Figure 10The structure of a working medium chamber 24 is shown as an example. The working medium chamber 24 contains a cooling medium 25 that can be converted from gas to liquid. When the power module 4 generates heat, the heat on the power module 4 is transferred to the radiator 2 and heats the cooling medium 25 in the radiator 2. When the cooling medium 25 is heated, at least part of the cooling medium 25 will turn into gas and flow along the cooling medium 25. Figure 9 The direction of the middle arrow D1 rises (the direction of D1 is the direction of the radiator 2 according to Figure 9 The gaseous cooling medium 25 transfers heat to the fins 23, and then exchanges heat with the cold source (air) through the fins 23, so that the gaseous cooling medium 25 quickly dissipates heat and condenses, gradually turning back into liquid cooling medium 25 and moving along the cooling medium 25. Figure 9 The direction of the middle arrow D2 is downward (the direction of D2 is the direction of the radiator 2). Figure 9 The example shown is installed in the downward direction), the liquid cooling medium 25 will turn into gaseous state after being heated next time, and the cycle will continue to dissipate heat for the power module 4.

[0075] Figure 9 The radiator 2 shown in the figure is an air-cooled two-phase working fluid radiator. In other examples, the radiator 2 can also be a liquid-cooled two-phase working fluid radiator (not shown in the drawings of this application). When the radiator 2 is a liquid-cooled two-phase working fluid radiator, after the power module 4 generates heat, the heat on the power module 4 will be transferred to the radiator 2 and heat the cooling working fluid 25 in the radiator 2. When the cooling working fluid 25 in the working fluid cavity 24 is heated, at least part of the cooling working fluid 25 will become gaseous and exchange heat with the cold source (liquid) through the radiator 2, so that the gaseous cooling working fluid 25 quickly dissipates heat and condenses, gradually turning back into liquid. The liquid cooling working fluid 25 will become gaseous again after being heated next time, and the cycle will continue to dissipate heat for the power module 4.

[0076] It should be noted that Figure 9 The radiator 2 in the figure is only a two-phase working medium radiator structure, and the directions of arrows D1 and D2 are also only Figure 9 In the example, the radiator 2 is installed to cool the moving direction of the working medium 25. In other examples, the structure of the two-phase working medium radiator can be specifically designed according to the installation position and direction of the power conversion device 101, and this application does not impose any specific restrictions on this.

[0077] In addition, in the example provided in this application, the radiator 2 also has a flow channel 26 for cooling liquid (for example, water) to flow, and the flow channel 26 is closer to the power module 4 than the heat exchange channel 21. Figure 6 In the example shown, when the radiator 2 is an air-cooled radiator, the plurality of fins 23 are located on the side of the flow channel 26 away from the power module 4, which means that the heat exchange channel 21 is located on the side of the flow channel 26 away from the power module 4. Figure 8 In the example shown, when the radiator 2 is a liquid cooling radiator, the heat exchange channel 21 is located on the side of the flow channel 26 away from the power module 4. Figure 10 In the example shown, when the radiator 2 is a two-phase working fluid radiator, the flow channel 26 is closer to the power module 4 than the working fluid cavity 24, that is, the heat exchange channel 21 and the working fluid cavity 24 are both located on the side of the flow channel 26 away from the power module 4. In this example, the present application does not limit the positional relationship between the heat exchange channel 21 and the working fluid cavity 24. The heat exchange channel 21 may be located on the side of the working fluid cavity 24 away from the power module 4, or the working fluid cavity 24 may be located on the side of the heat exchange channel 21 away from the power module 4, or other possible implementation methods may be used, which will not be repeated in this application.

[0078] The flow channel 26 may be a channel, or a combination of multiple channels. For example, the flow channel 26 may include multiple sub-flow channels 261. Figure 6 、 Figure 8 and Figure 10 In the example shown, multiple sub-channels 261 are arranged side by side and spaced apart. In the example where the channel 26 includes multiple sub-channels 261, each sub-channel 261 is closer to the power module 4 than the heat exchange channel 21, that is, each sub-channel 261 is located on the side of the heat exchange channel 21 facing the power module 4.

[0079] By providing the flow channel 26, when the power conversion device 101 is in normal operation (for example, the power conversion device 101 is not in an overload scenario), the heat dissipation requirements of the power module 4 can be met through the heat exchange channel 21 of the radiator 2. When the power conversion device 101 is in an overload scenario, the power conversion device 101 will provide a large current to the power grid to maintain stable operation of the power grid. Therefore, the power module 4 generates severe heat. In this case, coolant is introduced into the flow channel 26, so that the liquid cooling heat dissipation method of the flow channel 26 is combined with the air cooling function or liquid cooling function of the heat exchange channel 21. This can increase the heat exchange capacity of the radiator 2, further reduce the temperature of the power module 4, better dissipate heat for the power module 4 in an overload scenario, improve the overload capacity of the power conversion device 101, and enable the power conversion device 101 to operate stably.

[0080] In some examples, the power conversion device 101 may further include a container 5 and a driving device 6. Figure 11 The structure of a container 5 and a driving device 6 is shown as an example. The container 5 can be a liquid storage tank, a liquid storage box or a liquid storage cabinet, etc., and the present application does not limit this. The container 5 is used to contain the coolant, and the inlet and outlet of the flow channel 26 are both connected to the container 5 (the flow channel 26 is auxiliary reference Figure 10), for example, when the flow channel 26 includes multiple sub-flow channels 261, the inlet of the flow channel 26 is connected to the container 5 through a corresponding main pipe 51 and multiple branch pipes 52, and the outlet of the flow channel 26 is connected to the container 5 through a corresponding main pipe 51 and multiple branch pipes 52. The driving device 6 is connected to the container 5 and the heat exchange channel 21 (for example, through the corresponding main pipe 51), and the driving device 6 is used to drive the coolant to flow between the flow channel 26 and the container 5. The driving device 6 can be a micro water pump or other liquid driving device, and the driving device 6 can be disposed inside the housing 1 or outside the housing 1.

[0081] By providing the container 5 and the drive device 6, when it is necessary to assist the power module 4 in dissipating heat through the coolant in the flow channel 26, the drive device 6 can be turned on and driven by the drive device 6 to drive the coolant in the container 5 to flow into the flow channel 26 of the radiator 2. The coolant in the flow channel 26 will remove heat from the radiator 2 (part of the heat comes from the power module 4, and part of the heat may also come from other components on the circuit board 3), and then, driven by the drive device 6, return to the container 5. The coolant returning from the flow channel 26 of the radiator 2 to the container 5 is at a higher temperature. This part of the coolant will cool down in the container 5 and then, driven by the drive device 6, flow back to the radiator 2, thus circulating and continuously dissipating heat for the power module 4.

[0082] Among them, the overload scenario has the characteristics of large loss and short duration, that is, the temperature of the power module 4 is quite different in the non-overload scenario and the overload scenario. In one example, the drive device 6 can be turned on and off according to demand, for example, referring to Figure 11 The power conversion device 101 further includes one or more samplers 7, wherein the sampler 7 can be arranged on the circuit board 3, for example, Figure 11 The sampler 7 can also be encapsulated in the power module 4, and this application does not impose any specific restrictions on this.

[0083] The sampler 7 is used to obtain a parameter. The parameter can be the current value flowing into the power module 4 or the current value flowing out of the power module 4. For example, the sampler 7 is a current transformer, a Hall current sensor, etc. The parameter can also be the temperature value of the power module 4. For example, the sampler 7 is a temperature sensor. In addition, the parameter can include both the current value flowing into or out of the power module 4 and the temperature value of the power module 4.

[0084] In the example where the parameter acquired by the sampler 7 is the current value flowing into the power module 4, when the current flowing into the power module 4 is large enough, for example, when the current value flowing into the power module 4 is greater than or equal to the first threshold value, the power module 4 generates severe heat and the temperature of the power module 4 will rise significantly (or, the temperature of the power module 4 will be about to rise significantly), and the driving device 6 starts and drives the coolant to flow between the flow channel 26 and the container 5 to dissipate heat for the power module 4. When the current flowing into the power module 4 decreases, for example, when the current value flowing into the power module 4 is less than the first threshold value, the heat of the power module 4 will not be too severe and the temperature will also drop. At this time, the driving device 6 can stop running, that is, the driving device 6 no longer drives the coolant in the flow channel 26 to circulate, and the power module 4 can meet the heat dissipation and heat exchange requirements only through the heat exchange channel 21 of the radiator 2.

[0085] In the example where the parameter obtained by the sampler 7 is the current value flowing out of the power module 4, when the current flowing out of the power module 4 is large enough, for example, when the current value flowing out of the power module 4 is greater than or equal to the first threshold value, it proves that the current flowing through the power module 4 is large and the power module 4 is seriously heating up. The driving device 6 starts and drives the coolant to flow between the flow channel 26 and the container 5 to dissipate heat for the power module 4. When the current flowing out of the power module 4 decreases, for example, when the current value flowing out of the power module 4 is less than the first threshold value, it proves that the current flowing through the power module 4 decreases, the heating of the power module 4 decreases, and the temperature also decreases. At this time, the driving device 6 no longer drives the coolant in the flow channel 26 to circulate.

[0086] In the example where the parameter acquired by the sampler 7 is the temperature value of the power module 4, when the temperature of the power module 4 is high, for example, when the temperature value of the power module 4 is greater than or equal to the second threshold value, the driving device 6 is activated and drives the coolant to flow between the flow channel 26 and the container 5, thereby dissipating heat for the power module 4. When the temperature of the power module 4 decreases, for example, when the temperature value of the power module 4 is less than the second threshold value, the driving device 6 can stop operating, that is, the driving device 6 no longer drives the coolant in the flow channel 26 to circulate, and the power module 4 can achieve heat dissipation and heat exchange requirements only through the heat exchange channel 21 of the radiator 2.

[0087] In some examples, the parameter value at which the drive device 6 stops operating can be made smaller than the parameter at which the drive device 6 starts operating. For example, in an example where the parameter acquired by the sampler 7 is the current value flowing into or out of the power module 4, the drive device 6 stops operating only when the current value flowing into or out of the power module 4 is less than a third threshold value (the third threshold value is less than the first threshold value). For another example, in an example where the parameter acquired by the sampler 7 is the temperature value of the power module 4, the drive device 6 stops operating only when the temperature value of the power module 4 is less than a fourth threshold value (the fourth threshold value is less than the second threshold value).

[0088] This application sets the sampler 7 to collect the required parameters, and sets the start and stop conditions of the driving device 6, so that the first power device operates only when needed, thereby improving the transient heat exchange capability of the radiator 2, effectively coping with the problem of serious heating of the power module 4 in the overload scenario, and can also save energy and reduce consumption, making the instantaneous heat dissipation capability of the radiator 2 more targeted (for the power module 4 in the overload scenario), and more economically improving the overload capacity of the power conversion device 101.

[0089] In other examples, the current value flowing into or out of the power module 4 or the temperature value of the power module 4 can be obtained in other appropriate ways, and the operation or stop of the drive device 6 can be controlled by comparing the above values ​​with preset values.

[0090] In some other examples, the driving device 6 may also be normally open, that is, the flow channel 26 and the heat exchange channel 21 always cooperate with each other to jointly achieve heat dissipation for the power module 4.

[0091] Regarding the location of the container 5, in some examples, the housing 1 has an air inlet 12. Figure 12 The structure of an air inlet 12 is shown as an example, wherein: Figure 12 There are multiple air inlets 12 in the housing 1, and the container 5 is located at the air inlet 12. In addition, the container 5 is closer to the air inlet 12 than the radiator 2. The radiator 2 is connected to the power module 4 (heat source), that is, the radiator 2 is closer to the power module 4, and the area around the radiator 2 is easily affected by the temperature of the power module 4. The container 5 is closer to the air inlet 12 than the radiator 2, which can keep the container 5 away from the heat source and close to the air inlet 12. Among them, the wind entering the housing 1 from the air inlet 12 can exchange heat with the container 5, and the coolant with a higher temperature entering the container 5 (the coolant at this time has just absorbed part of the heat of the power module 4) can exchange heat with the airflow at the air inlet 12, so that the coolant in the container 5 can maintain a lower temperature as much as possible. In this way, the coolant in the container 5 can still effectively dissipate heat for the power module 4 after re-entering the flow channel 26, which is conducive to the recycling of the coolant.

[0092] Moreover, the flow channel 26 is closer to the power module 4 than the heat exchange channel 21 (the position relationship can be referred to Figure 10 ), so the low temperature requirement for the coolant in the flow channel 26 is higher. Since the container 5 is closer to the air inlet 12 than the radiator 2, the cooling speed and cooling effect inside the container 5 are better than the radiator 2. The coolant can be cooled better in the container 5. After the coolant in the container 5 enters the flow channel 26, it can take away more heat and quickly dissipate heat for the power module 4.

[0093] In addition, when the radiator 2 is a liquid-cooled radiator, the receiving member 8 may also be provided at the air inlet 12 .

[0094] In addition, the position of the air inlet 12 can also be set according to needs. Figure 12 Only one arrangement of the air inlet 12 is shown for example. In other examples, the air inlet 12 can be arranged on any one or more side walls of the shell 1, or on the top or bottom wall of the shell 1. This application does not impose any specific restrictions on this.

[0095] In other examples, the interior of the housing 1 may have at least two mutually separated accommodating cavities 13. Figure 13 The structure of a receiving cavity 13 is shown as an example, wherein: Figure 13 There are two accommodating cavities 13 in the housing 1, and the two accommodating cavities 13 are separated from each other by a frame 14. In other examples, the number of accommodating cavities 13 in the housing 1 can be three, four, and so on, and multiple accommodating cavities 13 can be separated from each other by a partition structure. The power module 4 and the container 5 are respectively located in different accommodating cavities 13. For example, the circuit board 3, the power module 4 and the radiator 2 are located in one of the accommodating cavities 13, and the container 5 is located in another accommodating cavity 13. Since the container 5 and the power module 4 are located in different accommodating cavities 13 in the housing 1, the heat of the power module 4 has little effect on the temperature of the container 5, and the coolant flowing into the container 5 can be quickly cooled at a lower ambient temperature, which is conducive to the recycling of the coolant. In the case where the radiator 2 is a liquid-cooled radiator, the accommodating member 8 can be set in the same accommodating cavity 13 as the container 5, or the accommodating member 8, the container 5 and the power module 4 can be set in three different accommodating cavities 13 respectively.

[0096] In some other examples, the container 5 may also be disposed at any suitable position outside the housing 1 , or the container 5 may also be disposed at other suitable positions inside the housing 1 .

[0097] In the present application, the flow channel 26 can be set at any suitable position between the heat exchange channel 21 and the power module 4. In one example, referring to Figure 14 , Figure 14The structure of a flow channel 26 is shown as an example. In the thickness direction of the power module 4 (direction D3), the flow channel 26 overlaps with the power module 4. That is, the heat sink 2 has a surface 27 for connecting to the power module 4, and the orthographic projection of the flow channel 26 on this surface 27 overlaps with the orthographic projection of the power module 4 on this surface 27. In this way, the flow path of the coolant in the flow channel 26 can pass through the location of the power module 4, so that the coolant in the flow channel 26 can better remove heat from the power module 4, which is beneficial for heat dissipation of the power module 4.

[0098] The thickness direction (direction D3 ) of the power module 4 is the distribution direction of the power module 4 and the heat sink 2 , and is also the thickness direction of the circuit board 3 .

[0099] Among them, Figure 14 In the example where the middle flow channel 26 includes multiple sub-flow channels 261 , as long as one sub-flow channel 261 overlaps with the power module 4 in the thickness direction of the power module 4 , it can be considered that the flow channel 26 and the power module 4 overlap.

[0100] In the example where the heat sink 2 has multiple flow channels 26 , as long as there is one flow channel 26 that overlaps with the power module 4 in the thickness direction of the power module 4 , it can be considered that the flow channel 26 and the power module 4 overlap.

[0101] Figure 15 The structure of another flow channel 26 is shown as an example. In this example, the flow channel 26 is a complete channel (that is, it is not divided into multiple sub-flow channels 261). In the thickness direction of the power module 4 (direction D3), the flow channel 26 and the power module 4 can also overlap, so as to fully dissipate heat for the power module 4.

[0102] Regarding the structure of the power module 4, in some examples, refer to Figure 16The power module 4 may include a substrate 41, a die 42 (die) and a package shell 43. A plurality of die 42 may be provided and fixed on the substrate 41 (each power module 4 may also include only one die 42). The substrate 41 may be a direct bonding copper ceramic substrate (DBC), or other substrates for carrying the die 42. The die 42 may be a diode, a silicon carbide (SiC) tube, a metal-oxide-semiconductor field-effect transistor (MOSFET), a gallium nitride (GaN) tube, a thyristor, an insulated gate bipolar transistor (IGBT), and the like. This application does not impose specific restrictions on this. The substrate 41 and the die 42 are both located in the package shell 43, which is connected to the heat sink 2. In the thickness direction of the substrate 41 (direction D3), the flow channel 26 and the die 42 overlap.

[0103] The thickness direction (direction D3 ) of the substrate 41 is the thickness direction of the power module 4 , the distribution direction of the power module 4 and the heat sink 2 , and the thickness direction of the circuit board 3 .

[0104] That is, the orthographic projection of the flow channel 26 on the surface 27 of the heat sink 2 and the orthographic projection of the die 42 on the surface 27 have an overlapping portion. Figure 17 The schematic diagram shows a top view of the positional relationship between the power module 4, the rear flow channel 26 of the heat sink 2, and the bare chip 42. Figure 16 and Figure 17 The flow channel 26 in FIG. 4 includes a plurality of sub-flow channels 261 . As long as at least one sub-flow channel 261 overlaps with the die 42 in the thickness direction of the substrate 41 , it can be considered that the flow channel 26 and the die 42 overlap. Figure 18 Another positional relationship between the flow channel 26 and the bare chip 42 after the power module 4 and the heat sink 2 is shown as an example from above. In this example, the number of sub-flow channels 261 is the same as the number of bare chips 42, and each sub-flow channel 261 overlaps with a corresponding bare chip 42.

[0105] In the example where the heat sink 2 has multiple flow channels 26 , as long as one flow channel 26 overlaps with the bare die 42 in the thickness direction of the substrate 41 , it can be considered that the flow channel 26 overlaps with the power module 4 .

[0106] In some other examples, when the flow channel 26 is a complete channel (ie, not divided into a plurality of sub-flow channels 261 ), the flow channel 26 and the die 42 may also overlap in the thickness direction of the substrate 41 .

[0107] In the example where the power module 4 includes a bare chip 42, the location of the bare chip 42 is an area where the power module 4 generates more heat (the bare chip 42 is the main heat source), and the flow channel 26 and the bare chip 42 overlap in the thickness direction of the substrate 41. That is, the coolant in the flow channel 26 will pass through the location of the bare chip 42 in the power module 4 during the flow process, and take away as much heat as possible around the bare chip 42, thereby dissipating heat for the bare chip 42 in a targeted manner, so that the heat dissipation efficiency of the radiator 2 of the present application is higher and the heat dissipation effect is better.

[0108] In addition, the cross-sectional area of ​​the flow channel 26 can be set according to requirements. For example, in an example where the radiator 2 is an air-cooled radiator, the radiator 2 includes a heat sink 22 and a plurality of fins 23. The ratio of the cross-sectional area of ​​the flow channel 26 to the cross-sectional area of ​​the heat sink 22 is less than or equal to 0.2, or in other words, the area occupied by the cross-sectional area of ​​the flow channel 26 on the cross-sectional area of ​​the heat sink 22 is less than or equal to 20%. For example, the ratio of the cross-sectional area of ​​the flow channel 26 to the cross-sectional area of ​​the heat sink 22 is 0.2. For another example, the ratio of the cross-sectional area of ​​the flow channel 26 to the cross-sectional area of ​​the heat sink 22 is 0.15. For another example, the ratio of the cross-sectional area of ​​the flow channel 26 to the cross-sectional area of ​​the heat sink 22 is 0.1.

[0109] The cross section of the flow channel 26 and the cross section of the heat sink 22 are parallel to each other, and the cross section of the flow channel 26 and the cross section of the heat sink 22 are both parallel to the thickness direction (direction D3 ) of the power module 4 .

[0110] Figure 19 A cross section of a heat sink 22 (shaded portion) is shown as an example. It should be noted that the cross section includes the cross section of the solid portion of the heat sink 22 and the cross section of the virtual portion of the heat sink 22 (for example, the cross section of the flow channel 26). Figure 20 An exemplary cross-section of a flow channel 26 (shaded portion) is shown. This cross-section represents only the cross-section of the flow channel 26. If the flow channel 26 includes multiple sub-flow channels 261, the cross-sectional area of ​​the flow channel 26 is the sum of the cross-sectional areas of the multiple sub-flow channels 261. By designing the cross-sectional area of ​​the flow channel 26 to be smaller, the heat dissipation effect of the radiator 2 is not significantly affected when no coolant flows through the flow channel 26. Air cooling can still play an important role in heat dissipation, thus reducing the impact of the flow channel 26 on the air cooling performance of the radiator 2.

[0111] For another example, in the case where the radiator 2 is a liquid-cooled radiator, the radiator 2 has both a heat exchange channel 21 and a flow channel 26. The volume of the heat exchange channel 21 is larger than that of the flow channel 26. In other words, the heat exchange channel 21 has a larger volume (and a stronger ability to carry liquid). Even when no coolant flows through the flow channel 26, the liquid in the heat exchange channel 21 can still meet the heat dissipation requirements of the power module 4, reducing the impact of the flow channel 26 on the heat dissipation capacity of the heat exchange channel 21.

[0112] The power modules 4 of the present application may be provided in plurality, and the plurality of power modules 4 may share one radiator 2 , or each power module 4 may correspond to one radiator 2 (in the case of multiple radiators 2 ).

[0113] The position of the power module 4 on the circuit board 3 in this application is for illustration only and is not a limitation to the power module 4 in this application.

[0114] The structure inside the housing 1 in this application is only an example. Figure 4 、 Figure 7 The locations of the pipes and devices inside the housing 1 are merely schematic illustrations and are not limitations to the present application.

[0115] The above description is merely a specific embodiment of the present application, but the scope of protection of the present application is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in this application should be included in the scope of protection of this application. Therefore, the scope of protection of this application should be based on the scope of protection of the claims.

Claims

1. A power conversion device, characterized in that: The power conversion device includes a housing, a power module and a radiator; wherein, The housing is used to accommodate the power module, and the power module is used to convert direct current from the photovoltaic module or the energy storage battery into alternating current; The radiator is at least partially located in the housing and connected to the power module, and has a heat exchange channel, and the heat exchange channel is used for airflow or liquid to pass through; The radiator further has a flow channel inside for the flow of coolant, and the flow channel is closer to the power module than the heat exchange channel.

2. The power conversion device according to claim 1, characterized in that The power conversion device also includes a container and a driving device, the container is used to accommodate the coolant, the inlet and outlet of the flow channel are both connected to the container, and the driving device is used to drive the coolant to flow between the flow channel and the container.

3. The power conversion device according to claim 2, characterized in that: The driving device is used to drive the coolant to flow when the current value flowing into or out of the power module is greater than or equal to a first threshold.

4. The power conversion device according to claim 2, characterized in that The driving device is used to drive the coolant to flow when the temperature value of the power module is greater than or equal to a second threshold.

5. The power conversion device according to any one of claims 2 to 4, characterized in that: The shell has at least two mutually separated accommodating cavities inside, and the power module and the container are respectively located in different accommodating cavities.

6. The power conversion device according to any one of claims 2 to 4, characterized in that: The shell has an air inlet, the container is fixed in the shell and located at the air inlet, and the container is closer to the air inlet than the radiator.

7. The power conversion device according to any one of claims 1 to 4, characterized in that: In a thickness direction of the power module, the flow channel overlaps with the power module.

8. The power conversion device according to claim 7, characterized in that: The power module includes a substrate, a bare chip and a packaging shell. The packaging shell is used to accommodate the substrate and the bare chip. The bare chip is fixed on the substrate. The packaging shell is connected to the heat sink. In the thickness direction of the substrate, the flow channel and the bare chip overlap.

9. The power conversion device according to any one of claims 1 to 4, characterized in that: The heat exchange channel is located in the radiator and is used for allowing the liquid to pass through. The volume of the heat exchange channel is greater than the volume of the flow channel.

10. The power conversion device according to any one of claims 1 to 4, characterized in that: The radiator includes a heat sink and multiple fins. The flow channel is located in the heat sink. The heat sink is connected to the power module. The multiple fins are fixed on the side of the heat sink facing away from the power module. The heat exchange channel includes a gap between two adjacent fins.

11. The power conversion device according to claim 10, characterized in that: The ratio of the cross-sectional area of ​​the flow channel to the cross-sectional area of ​​the heat sink is less than or equal to 0.2, and the cross-sectional area of ​​the flow channel and the cross-sectional area of ​​the heat sink are parallel to each other and parallel to the thickness direction of the power module.

12. The power conversion device according to claim 10, characterized in that: The radiator further has a working medium cavity inside, in which a cooling medium capable of gas-liquid conversion is contained. The flow channel is closer to the power module than the working medium cavity.

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