CN119093697A

CN119093697A - Power modules and power systems

Info

Publication number: CN119093697A
Application number: CN202411064091.5A
Authority: CN
Inventors: 肖波; 黄朱勇; 刘汉华; 林臻; 杨江其
Original assignee: Huawei Digital Power Technologies Co Ltd
Current assignee: Huawei Digital Power Technologies Co Ltd
Priority date: 2021-08-26
Filing date: 2021-08-26
Publication date: 2024-12-06
Also published as: CN113890309A; CN113890309B

Abstract

The embodiment of the application discloses a power module and a power system, wherein the power module comprises a shell, an input end, an output end and a plurality of power units connected in series, the input end is used for connecting a power supply and the power units, the output end is used for outputting voltage after the power units are transformed, the power units are spatially divided into a first layer and a second layer, each layer comprises at least one power unit, the shell comprises a first cover plate, a second cover plate and a third cover plate which are arranged in a stacked mode, the second cover plate is positioned between the first cover plate and the third cover plate, the first layer of power units is arranged on one side, close to the second cover plate, of the first cover plate, the second cover plate is arranged on one side, close to the second cover plate, of the third cover plate, and the first cover plate, the second cover plate and the third cover plate are connected. Therefore, the first cover plate and the third cover plate can adopt a buckling installation mode, a plurality of power units are packaged in the shell, and the installation mode is simple.

Description

Power module and power supply system

The present application is a divisional application, the application number of the original application is 202110991195.0, the original application date is 26 of 08 month of 2021, and the whole content of the original application is incorporated by reference into the present application.

Technical Field

The embodiment of the application relates to the technical field of power electronics, in particular to a power module and a power supply system.

Background

At present, along with the rapid development of novel AC/DC power distribution network technology, a transformer is required to convert kV-level input voltage into low voltage of hundreds of volts to supply power for electric equipment.

Fig. 1 is a simplified schematic diagram of a power system architecture. As shown in fig. 1, the power supply system comprises a power supply 01, a power frequency transformer 02, an uninterruptible power supply (uninterruptible power supply, UPS) system 04 and electric equipment 03, wherein the power frequency transformer 02 is used for transforming the voltage input by the power supply 01 and outputting the transformed voltage to the UPS system 04, and the UPS system 04 is used for stabilizing the commercial power and supplying the stabilized voltage to the electric equipment 03.

However, the power frequency transformer 02 and the UPS system 04 occupy a large space, which is disadvantageous for miniaturization of the apparatus.

For this reason, the prior art provides a power electronic transformer which can be used in a power supply system with a more space saving. Fig. 2 is a schematic diagram of a power electronic transformer. As shown in fig. 2, the power electronic transformer 05 has a two-layer structure, i.e., a first layer 0001 and a second layer 0002. Wherein the first layer 100 comprises power cell 001, power cell 002, power cell 003 and power cell 004, and the second layer 200 comprises power cell 005, power cell 006, power cell 007 and power cell 008.

When the voltage difference between the adjacent power units is too large, the power units are easy to break down to cause ignition, as shown in fig. 2, an insulating housing 051 may be disposed outside each power unit.

However, the insulating housing 051 is of a single four-side closed structure, so that each power unit is large in size, low in utilization rate, high in material space ratio, low in insulating material utilization rate and low in power density.

Disclosure of Invention

The embodiment of the application provides a power module and a power supply system, which solve the problem of large occupied space of the power supply system.

In order to achieve the above purpose, the embodiment of the application adopts the following technical scheme:

According to a first aspect of the embodiment of the application, a power module is provided, which comprises a shell, an input end, an output end and a plurality of power units connected in series, wherein the input end is used for connecting a power supply and the power units, the output end is used for outputting voltage after the power units are transformed, the power units are spatially divided into a first layer and a second layer, each layer comprises one or more power units, the shell comprises a first cover plate, a second cover plate and a third cover plate which are arranged in a stacked mode, the second cover plate is located between the first cover plate and the third cover plate, the first layer of power units is arranged on one side, close to the second cover plate, of the first cover plate, the second layer of power units is arranged on one side, close to the second cover plate, of the third cover plate, and the first cover plate, the second cover plate and the third cover plate are connected. Thus, the first cover plate, the second cover plate and the third cover plate are an upper part, a middle part and a lower part, all power units of the first layer can be positioned between the first cover plate and the second cover plate, and all power units of the second layer can be positioned between the second cover plate and the third cover plate. In particular, all power cells of the first layer may be mounted on the first cover plate or on the second cover plate. All power cells of the second layer may be mounted on the third cover plate or on the second cover plate. For example, the first cover plate, the second cover plate and the third cover plate can be assembled together in a buckling installation mode, a plurality of power units are packaged in the shell, and the installation mode is simple. Meanwhile, for an application scene of adopting a series connection mode with smaller voltage difference between adjacent power units in the same layer in a plurality of power units, as the power module does not need to arrange an insulating structure between the adjacent power units in the same layer, the material utilization rate and the power density are improved, and the adjacent power units in the same layer are not easy to break down to cause ignition. .

In an alternative implementation manner, the first layer and the second layer each include a plurality of the power units, and all the power units in the same layer are sequentially connected in series. And, one power unit that is located the tip in the first layer and one power unit that is located the tip in the second layer are connected in series for the voltage difference between the adjacent power unit of same floor is as little as possible, further reduces the problem that is liable to be broken down and leads to the ignition between the adjacent power unit of same floor.

In an alternative implementation, the first cover plate, the second cover plate, and the third cover plate are all made of insulating materials. By providing an insulating cover plate, the power units of two adjacent layers can be prevented from being broken down by higher voltage to strike fire.

In an alternative implementation manner, conductive layers are arranged on the outer sides of the first cover plate and the third cover plate, and one or more first shielding layers are arranged in the first cover plate. When a first shielding layer is disposed in the first cover plate, the first shielding layer may be opposite to and connected with all the power units of the first layer. When a plurality of first shielding layers are arranged in the first cover plate and the number of the power units of the first layer is one, the power units of the first layer can be opposite to and connected with any one or a plurality of the first shielding layers. When the first cover plate is provided with a plurality of first shielding layers and the number of the power units of the first layer is multiple, the plurality of first shielding layers are opposite to the plurality of power units of the first layer one by one, and each power unit positioned on the first layer is connected with one or more corresponding first shielding layers. For example, one power cell of the first layer is connected to one first shielding layer by a lead. One or more second shielding layers are arranged in the third cover plate. When a second shielding layer is provided in the third cover plate, the second shielding layer may be connected to all power cells of the second layer. When a plurality of second shielding layers are arranged in the third cover plate and the number of the power units of the second layer is one, the power units of the second layer can be opposite to and connected with any one or a plurality of the second shielding layers. When the third cover plate is provided with a plurality of second shielding layers and a plurality of power units of the second layer, the plurality of second shielding layers are opposite to the plurality of power units of the second layer one by one, and each power unit positioned on the second layer is connected with one or a plurality of corresponding second shielding layers. For example, one power cell of the second layer is connected to one second shielding layer by a lead. Therefore, the conducting layers on the outer sides of the first cover plate and the third cover plate can be used as grounding plates, the shielding layers are arranged in the first cover plate and the third cover plate, and the power units and the shielding layers can be connected through the leads, wherein the leads can conduct the power units and the shielding layers, and insulating materials are filled between the shielding layers and the conducting layers, so that the insulating performance is improved, and the power units and the grounding plates are prevented from being ignited due to the fact that air breaks down by higher voltage.

In an alternative implementation, one or more third shielding layers are provided in the second cover plate, and all third shielding layers may be located below the power cells of the first layer. When a third shielding layer is disposed in the second cover plate, the third shielding layer may be opposite to and connected with all the power units of the first layer. When a plurality of third shielding layers are arranged in the second cover plate and the power units of the first layer are one, the power units of the first layer can be opposite to and connected with any one or a plurality of the third shielding layers. When the second cover plate is provided with a plurality of third shielding layers and the power units of the first layer are a plurality of, the plurality of third shielding layers are opposite to the plurality of power units of the first layer one by one, and each power unit positioned on the first layer is connected with one or a plurality of corresponding third shielding layers. For example, one power cell of the first layer is connected to a third shielding layer by a wire. Therefore, the third shielding layer is arranged in the second cover plate, and the power unit and the third shielding layer are conducted through the lead, so that the adjacent first-layer power unit and the second cover plate can be prevented from being broken down due to the existence of an air gap, and the insulation performance between the first-layer power unit and the second-layer power unit is improved.

In an alternative implementation, one or more fourth shielding layers are disposed in the second cover plate, and all the fourth shielding layers may be located above the power cells of the second layer and below the third shielding layer. When a fourth shielding layer is provided in the second cover plate, the fourth shielding layer may be connected to all power cells of the second layer. When a plurality of fourth shielding layers are arranged in the second cover plate and the power units of the second layer are one, the power units of the second layer can be opposite to and connected with any one or a plurality of the fourth shielding layers. When the second cover plate is provided with a plurality of fourth shielding layers and the number of the power units of the second layer is multiple, the fourth shielding layers are opposite to the power units of the second layer one by one, and each power unit positioned on the second layer is connected with one or more corresponding fourth shielding layers. For example, one power cell of the second layer is connected to one fourth shielding layer by a lead. Therefore, the fourth shielding layer is arranged in the second cover plate, and the power unit and the fourth shielding layer are conducted through the lead, so that the adjacent second-layer power unit and the second cover plate can be prevented from being broken down due to the existence of an air gap, and the insulation performance between the first-layer power unit and the second-layer power unit is improved.

In an alternative implementation manner, the first cover plate includes a top plate and a first connecting plate that are connected, the third cover plate includes a bottom plate and a third connecting plate that are connected, the top plate is opposite to the bottom plate, the first connecting plate is located between the top plate and the second cover plate, the third connecting plate is located between the bottom plate and the second cover plate, the first connecting plate is opposite to the third connecting plate, and a first gap is provided between the first connecting plate and the third connecting plate. Thus, no shielding layer is provided at the first slit, so that the first slit can act as an electrical gap, where an electric field can be generated.

In an alternative implementation, a fifth shielding layer is provided in the first connection plate, the fifth shielding layer being opposite to the one or more power cells located in the first layer. And, the fifth shielding layer may be electrically connected to one or more power cells in the corresponding first layer. For example, the fifth shield layer is connected to one power cell by a lead. Therefore, the fifth shielding layer is arranged in the first connecting plate, and the power unit and the fifth shielding layer are conducted through the lead, so that the adjacent first-layer power unit and the first connecting plate can be prevented from being broken down due to the existence of an air gap, and the insulation performance between the first-layer power unit and the second-layer power unit is further improved.

In an alternative implementation, a sixth shielding layer is provided in the third connection board, the sixth shielding layer being opposite to the one or more power cells located in the second layer. And, the sixth shielding layer may be electrically connected to one or more power cells in the corresponding second layer. For example, the sixth shielding layer is connected to one power cell by a lead. Therefore, the sixth shielding layer is arranged in the third connecting plate, and the power unit and the sixth shielding layer are conducted through the lead, so that the adjacent second-layer power unit and the third connecting plate can be prevented from being broken down due to the existence of an air gap, and the insulation performance between the first-layer power unit and the second-layer power unit is further improved.

In an alternative implementation manner, the second cover plate comprises a second connecting plate, wherein the second connecting plate is positioned on the inner sides of the first connecting plate and the third connecting plate, a second gap is formed between the second connecting plate and the first connecting plate, and a third gap is formed between the second connecting plate and the third connecting plate. Therefore, by arranging the second connecting plate to form a second gap and a third gap which are used as electric gaps, the creepage distance between the shielding layer and the conducting layer can be increased, and the electric field intensity is reduced.

In an alternative implementation, an end of the first connecting plate near the third connecting plate is chamfered. The chamfer can be a circular arc chamfer or a rectangular chamfer. Thereby, the electric gap between the first connection plate and the third connection plate can be further increased, and the electric field strength can be reduced.

In an alternative implementation, an end of the third connecting plate near the first connecting plate is chamfered. The chamfer can be a circular arc chamfer or a rectangular chamfer. Thereby, the electric gap between the first connection plate and the third connection plate can be further increased, and the electric field strength can be reduced.

In an alternative implementation manner, a circular arc chamfer or a rectangular chamfer is adopted on one side of the second connecting plate, which is close to the first connecting plate and the third connecting plate. Thereby, the electric gap between the first connection plate, the second connection plate and the third connection plate can be further increased, and the electric field intensity can be reduced.

In an alternative implementation manner, positioning columns are arranged on the first cover plate and the third cover plate, positioning holes are arranged on the second cover plate, and the positioning columns are opposite to the positioning holes one by one. And the positioning column can be inserted into the positioning hole. From this, through setting up reference column and locating hole, reduced the installation degree of difficulty between first apron and the third apron.

In an alternative implementation, the device further includes a housing, the housing is disposed around the housing, and the housing is connected to the housing. Thus, the housing can protect the power module.

In an alternative implementation, the housing is made of metal. Therefore, the shell has better heat dissipation performance and higher stability.

In an alternative implementation, the casing is provided with heat dissipation holes. Thereby, the heat dissipation performance of the power module can be improved.

In a second aspect of the embodiment of the present application, a power supply system is provided, where the power supply system includes a power supply, an electric device, and a power module as described above, the power supply is connected to an input end of the power module, and the electric device is connected to an output end of the power module. Therefore, the power supply system adopts the power module, is smaller in size and can reduce occupied space.

Drawings

FIG. 1 is a simplified schematic diagram of a power system architecture;

FIG. 2 is a schematic diagram of a power electronic transformer;

fig. 3 is a schematic structural diagram of a power module according to an embodiment of the present application;

Fig. 4 is a schematic diagram of a disassembled structure of a power module according to an embodiment of the present application;

Fig. 5 is a front view of a power module according to an embodiment of the present application;

fig. 6 is a schematic structural diagram of a housing of a power module according to an embodiment of the present application;

fig. 7 is a schematic diagram of a disassembled structure of a housing of a power module according to an embodiment of the present application;

FIG. 8 is a cross-sectional view A-A of FIG. 6;

Fig. 9 is a schematic diagram of internal routing of a power module according to an embodiment of the present application;

FIG. 10 is a circuit diagram of the power module of FIG. 9;

FIG. 11 is a diagram illustrating an electric field distribution of a power module according to an embodiment of the present application;

fig. 12 is a schematic structural diagram of another power module according to an embodiment of the present application;

Fig. 13 is a schematic diagram illustrating a disassembled structure of the power module in fig. 12.

Detailed Description

In order to make the objects, technical solutions and advantages of the present application more apparent, the present application will be further described in detail with reference to the accompanying drawings.

Hereinafter, the terms "first," "second," and the like are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defining "a first", "a second", etc. may explicitly or implicitly include one or more such feature. In the description of the present application, unless otherwise indicated, the meaning of "a plurality" is two or more.

Furthermore, in the present application, directional terms "upper", "lower", etc. are defined with respect to the orientation in which the components are schematically disposed in the drawings, and it should be understood that these directional terms are relative concepts, which are used for description and clarity with respect thereto, and which may be changed accordingly in accordance with the change in the orientation in which the components are disposed in the drawings.

In the present application, unless explicitly stated and limited otherwise, the term "coupled" is to be construed broadly, and for example, the term "coupled" may be a fixed connection, a removable connection, or an integral unit, and may be directly or indirectly coupled via an intervening medium.

In order to enable the person skilled in the art to better understand the technical scheme provided by the embodiment of the application, the method can be applied to any power units which need to be spatially distributed into at least two layers, and the two adjacent layers need to be connected in series, and the power units are connected in series to form a certain voltage difference or are connected with a power supply with the certain voltage difference.

The embodiment of the application provides a power supply system which comprises a power supply, electric equipment and a power module, wherein the power supply is connected with the input end of the power module, and the electric equipment is connected with the output end of the power module.

The power module is used for converting input alternating current into direct current. If the power system is applied to a data center, the powered device may be a server in the data center.

For example, the ac power input to the power module may be ac medium voltage, the dc power output may be dc low voltage, and the data center may employ a power system to convert the ac medium voltage to the dc low voltage, thereby powering the servers in the data center.

For example, when the power grid enters a building (i.e., the building where the data center is located), the power supply is three-phase 10kV alternating current (which can be regarded as alternating current input by the power module), and the three-phase 10kV alternating current is converted into 400V direct current after voltage conversion by the power supply system, and the 400V direct current can supply power for terminal internet technology (internet technology, IT) equipment (e.g., a server) in the data center.

The existing power module is large in occupied space, low in power density and high in installation difficulty, and needs to be matched with a UPS system, so that the embodiment of the application provides the power module with small occupied space.

Fig. 3 is a schematic structural diagram of a power module according to an embodiment of the present application. Fig. 4 is a schematic diagram of a disassembled structure of a power module according to an embodiment of the present application. Fig. 5 is a front view of a power module according to an embodiment of the present application. As shown in fig. 3, 4 and 5, the power module 10 includes an input terminal (not shown), an output terminal (not shown), a housing 100, and a plurality of power cells (power cells 1-8) connected in series.

The embodiment of the application is not particularly limited to a specific implementation form of the power unit, and the power unit can be a power conversion unit or a battery cell, for example.

In some embodiments, the power unit is a power conversion unit, and the power conversion unit externally presents two terminals, and the two terminals can be not distinguished from each other, so long as the two terminals are connected in series with the terminals of other power conversion units.

In other embodiments, the power units are battery cells, each battery cell serves as a small power source and has an anode and a cathode, and when the plurality of battery cells are connected in series, attention is paid to the connection relationship between the anode and the cathode of each battery cell, for example, the anode of the first battery cell serves as the anode of the battery power unit, the cathode of the first battery cell is connected with the anode of the second battery cell, the cathode of the second battery cell is connected with the anode of the third battery cell, and so on until the cathode of the last battery cell serves as the cathode of the battery power unit.

The power unit comprises a power supply, an input end, an output end and a plurality of power units, wherein the input end is used for connecting the power supply and the power units, the output end is used for outputting voltage after the power units are transformed, the power units are spatially divided into at least two layers, and each layer comprises at least one power unit.

As shown in fig. 3, the power module 10 provided in this embodiment is a plurality of power cells spatially arranged in at least two layers, a first layer 1001 and a second layer 1002.

The first layer 1001 and the second layer 1002 each include one or more power cells. The number of the plurality of power cells may be two or more, and the specific number of the power cells per layer is not particularly limited. Adjacent power cells of the first layer 1001 may be connected in series, adjacent power cells of the second layer 1002 may also be connected in series, and one power cell of the first layer 1001 is connected in series with one power cell of the second layer 1002. The sequential series connection of the power cells of the first layer 1001 and the power cells of the second layer 1002 may reduce the voltage difference between the partial power cells of the first layer 1001 and the partial power cells of the second layer 1002.

For example, when the application scenario corresponding to fig. 3 is 10kV high voltage, one power module 10 includes 8 power units, and the 8 power units in fig. 3 are respectively power unit 1-power unit 8. The power units 1-8 are sequentially connected in series, and the voltage born by each power unit is 10kV/8.

For ease of understanding, the following description will be given by taking an example in which the power cells included in the power module 10 are arranged in two layers. If the voltage class is higher or the voltage stress born by each power unit is smaller, the number of the power units can be increased, the embodiment of the application is not limited in particular, and the number of the power units arranged in each layer is only described by taking 4 as an example in the embodiment, and more or fewer power units can be set, particularly looking at the size requirement of the power cabinet.

When the product is realized, in order to effectively utilize the space distribution of the power module 10, the number of the power units of each layer can be equal, and the power units are symmetrically and uniformly distributed, so that the space can be saved, and more power units can be placed in a limited space.

The following series connection of the power cells of the first and second layers is illustrated.

When the first layer 1001 and the second layer 1002 each include only one power cell, the power cells of the first layer 1001 may be directly connected in series with the power cells of the second layer 1002.

When one of the first layer 1001 and the second layer 1002 includes only one power unit and the other of the first layer 1001 and the second layer 1002 includes two or more power units, the first layer 1001 includes two or more power units, the second layer 1002 includes only one power unit, for example, all the power units of the first layer 1001 may be sequentially connected in series, and one power unit located at a connection end in the first layer 1001 is connected in series with the power unit of the second layer 1002.

When the first layer 1001 and the second layer 1002 each include a plurality of power cells, a portion of the power cells in the first layer 1001 may be directly connected in series with a portion of the power cells in the second layer 1002. When a portion of the power cells in the first layer 1001 are directly connected in series with a portion of the power cells in the second layer 1002, the remaining power cells in the first layer 1001 are connected in series within the layer.

For example, the 1 st to nth power cells are sequentially arranged from the first side of the first layer 1001 to the second side of the first layer 1001. The (n+1) -th to (2 n) -th power cells are sequentially arranged from the first side of the second layer 1002 to the second side of the second layer 1002.

The 1 st to m th power cells in the first layer may be sequentially connected in series, wherein 1< m < n. Thereafter, the mth power cell in the first layer is connected in series with the n+1th power cell of the second layer. Then, the (n+1) th to(s) th power cells of the second layer are sequentially connected in series. Wherein n+1< s <2n. The s-th power cell of the second layer is then connected in series with the m+1-th power cell of the first layer. Then, the (m+1) th to (n) th power cells of the first layer are sequentially connected in series. Thereafter, the nth power cell of the first layer is connected in series with the (s+1) th power cell of the second layer. Finally, the (s+1) th power unit to the (2 n) th power unit of the second layer are sequentially connected in series. The voltage difference between two adjacent power units in the 1 st to m th power units, the n+1th to s th power units, the m+1th to n th power units, and the s+1th to 2n th power units is smaller. As shown in fig. 3, the first layer 1001 includes 4 power cells, namely, power cell 1-power cell 4 from left to right, namely, from the first side to the second side, and the second layer 1002 includes 4 power cells, namely, power cell 5-power cell 8 from left to right, namely, from the first side to the second side. The above numbers are merely for convenience of description, and are not meant to be in any sense, and may be numbered in other order.

That is, in order to make the voltage difference between the power cells in the two layers more uniform, it may be adopted that the power cells of the first layer 1001 and the power cells of the second layer 1002 are directly connected in series in order, and taking the first layer 1001 including the power cells 1 to 4 and the second layer 1002 including the power cells 5 to 8 as an example, as shown in fig. 3, the power cells 1 to 4 in the first layer 1001 are connected in series, the power cells 5 to 8 in the second layer 1002 are connected in series, and the power cells 4 in the first layer 1001 are connected in series with the power cells 5 in the second layer 1002.

It should be noted that, the first layer 1001 and the second layer 1002 are for convenience of description, and the positions of the two layers may be interchanged, which has no special meaning.

Each power unit comprises two ports, the ports can be input and output independently, the first port of the power unit 1 is connected with a power supply, the second port of the power unit 1 is connected with the first port of the power unit 2, the second port of the power unit 2 is connected with the first port of the power unit 3, the second port of the power unit 3 is connected with the first port of the power unit 4, the second port of the power unit 4 is connected with the first port of the power unit 5, the second port of the power unit 5 is connected with the first port of the power unit 6, the second port of the power unit 6 is connected with the first port of the power unit 7, the second port of the power unit 7 is connected with the first port of the power unit 8, and the second port of the power unit 8 is used as an output end.

Based on the above, since the power units between two adjacent power units in the power module 10 provided by the embodiment are sequentially and directly connected in series, effective voltage sharing around each shielding layer is realized, that is, the voltage differences between the adjacent power units in each layer are almost equal, so that the adjacent power units can be more effectively protected from breakdown caused by higher voltage differences. For example, the voltage difference between the power units 1 and 2 is equal to the voltage difference between the power units 2 and 3 and is also equal to the voltage difference between the power units 3 and 4 under the condition of neglecting errors, and similarly, the power units in each layer shown in fig. 3 are directly connected in series, so that the voltage equalizing effect can be better realized. When the power units are in a series connection relationship as shown in fig. 3, the adjacent modules on the same layer can be free from an insulating structure, so that insulating materials can be saved.

It should be noted that, part of the power units in the power module 10 are not used for voltage transformation, for example, the first port of the power unit 1 is used as an input end connected to a power source, and the power units 1 to 7 are connected in series through the ports in sequence, and then the second port of the power unit 7 is used as an output end.

The housing 100 is provided outside the power unit, for example. The housing 100 includes at least a first cover plate 101, a second cover plate 102, and a third cover plate 103 that are stacked, the second cover plate 102 being located between the first cover plate 101 and the third cover plate 103.

The power cells (power cells 1-4) of the first layer 1001 are disposed on a side of the first cover 101 close to the second cover 102, and the power cells (power cells 5-8) of the second layer 1002 are disposed on a side of the third cover 103 close to the second cover 102. All power cells of the first layer 1001 may be mounted on the first cover plate or on the second cover plate. All power cells of the second layer may be mounted on the third cover plate 103 or on the second cover plate 102. The following description will be given by taking an example in which all the power cells of the first layer 1001 are mounted on the first cover plate 101, and all the power cells of the second layer 1002 are mounted on the third cover plate 103.

The first cover plate 101, the second cover plate 102 and the third cover plate 103 are connected. The first cover plate 101, the second cover plate 102 and the third cover plate 103 can be fixedly connected in a welding mode, and can also be detachably connected by adopting connecting pieces (such as bolts or screws). Therefore, the first cover plate 101, the second cover plate 102 and the third cover plate 103 are divided into an upper part, a middle part and a lower part, a plurality of power units can be mounted on the first cover plate 101 and the third cover plate 103, for example, a butt-buckling mounting mode can be adopted, the first cover plate 101, the second cover plate 102 and the third cover plate 103 are assembled together, and therefore the power units are packaged in the shell, and the mounting mode is simple.

Meanwhile, the power units of each layer in the embodiment of the application are directly connected in series, so that the voltage equalizing effect can be better realized, an insulating structure is not required to be arranged between the adjacent power units of the same layer, the material utilization rate and the power density are improved, and the cover plate material is saved.

However, as shown in fig. 3, the power units 1 to 8 are serially connected in sequence, the first terminal of the power unit 1 is connected to one phase voltage, and the first terminal of the power unit 8 is connected to another phase voltage, that is, the voltage difference born between the power unit 1 and the power unit 8 is the line voltage U between the two phases. Since 8 power units are connected in series, each power unit receives a voltage of U/8, the voltage difference between the power unit 2 and the power unit 7 is 3U/4, and the voltage difference between the power unit 3 and the power unit 6 is U/2. Therefore, the voltage difference between adjacent power units in different layers is large, and breakdown and fire are easy to cause.

In the case of the present embodiment, the first cover 101, the second cover 102, and the third cover 103 are made of an insulating material, such as epoxy resin, for example.

The second cover plate 102 is located between the power cells of the first layer 1001 and the power cells of the second layer 1002, and can reduce a voltage difference between the power cells of the upper and lower layers, preventing a breakdown fire due to the voltage difference being too large.

Therefore, in the serial connection manner provided by the embodiment of the application, the second cover plate 102 can be arranged between the power units of the first layer 1001 and the power units of the second layer 1002, so that the voltage difference between the power units of the upper layer and the lower layer can be reduced, and the breakdown and the fire due to the too large voltage difference can be prevented.

The specific structures of the first cover plate 101, the second cover plate 102, and the third cover plate 103 are not limited in the embodiment of the present application.

Fig. 6 is a schematic structural diagram of a housing of a power module according to an embodiment of the present application. Fig. 7 is a schematic diagram of a disassembled structure of a housing of a power module according to an embodiment of the present application. As shown in fig. 6 and 7, the first cover 101 includes a top plate 1010 and two first connection plates 1011, the top plate 1010 and the two first connection plates 1011 form a concave structure, and the top plate 1010 and the two first connection plates 1011 may be integrally formed.

The second cover plate 102 includes a middle plate 1020 and two second connecting plates 1021, the second connecting plates 1021 and the middle plate 1020 form an H-shaped structure, and the middle plate 1020 and the two second connecting plates 1021 may be integrally formed.

The third cover plate 103 includes a base plate 1030 and two third connection plates 1031, the base plate 1030 and the two third connection plates 1031 form a concave structure, and the base plate 1030 may be integrally formed with the two third connection plates 1031.

In addition, as shown in fig. 7, a first positioning column 10101 is further provided on the top plate 1010, and the first positioning column 10101 may divide the top plate 1010 into a plurality of regions, and each region may be provided with one power unit. The base 1030 is further provided with a plurality of second positioning columns 10301, and the second positioning columns 10301 can divide the base 1030 into a plurality of areas, and each area can be provided with a power unit.

As shown in fig. 7, the middle plate 1020 is provided with connecting holes 10201, and the first positioning posts 10101 on the top plate 1010, the second positioning posts 10301 on the bottom plate 1030, and the positioning holes 10201 on the middle plate 1020 are opposite to each other, so that the first positioning posts 10101 on the top plate 1010 and the second positioning posts 10301 on the bottom plate 1030 can be inserted into the positioning holes 10201 on the middle plate 1020 when positioned, so as to assemble the first cover plate 101, the second cover plate 102, and the third cover plate 103 together.

In assembly, one layer of power cells may be mounted to the third cover plate 103 while another layer of power cells is mounted to the first cover plate 101.

The second cover plate 102 may then be covered onto the third cover plate 103, such that the positioning posts 10101 on the bottom plate 1030 are inserted into the positioning holes 10201 on the middle plate 1020, where the middle plate 1020 is opposite to the bottom plate 1030, and the second connecting plate 1021 is located inside the third connecting plate 1031. The base 1030 and intermediate panel 1020 may then be removably connected together by a connector.

The connecting member may be a bolt, and the connecting hole may be a bolt hole.

Finally, the first cover plate 101 may be covered onto the second cover plate 102, so that the positioning posts 10101 on the top plate 1010 are inserted into the positioning holes 10201 of the middle plate 1020, and at this time, the middle plate 1020 is opposite to the top plate 1010, and the second connecting plate 1021 is located inside the first connecting plate 1011. Likewise, the intermediate panel 1020 and the top panel 1010 may be detachably connected together by a connector.

Therefore, the insulating material consists of an upper part, a middle part and a lower part, and a plurality of power units can be packaged in one insulating material by adopting a butt-buckling installation mode.

The outer surface of the housing 100 is provided with a conductive layer 104 as shown in fig. 8, and one or more shielding layers (a first shielding layer 1012, a second shielding layer 1032, a third shielding layer 1022 and a fourth shielding layer 1023 as shown in fig. 8) are embedded in the housing 100, and the power unit may be connected to the shielding layers through leads.

Fig. 8 is a cross-sectional view A-A of fig. 6. As shown in fig. 8, a conductive layer 104 is disposed on the outer side of the housing 100, and the conductive layer 104 may serve as a ground plate. The conductive layer 104 includes a first conductive layer 1041 disposed on an outer side surface of the first cover plate 101, and a second conductive layer 1042 disposed on an outer side surface of the third cover plate 103.

And a shielding layer is arranged in the cover plate between the power unit and the conducting layer, and the power unit is electrically connected with the shielding layer.

Referring next to fig. 8, a first shielding layer 1012 is disposed in the first cover plate 101, and the first shielding layer 1012 may be one or more. Fig. 8 shows 4 first shield layers 1012,4 first shield layers 1012, which are a shield layer 1012a, a shield layer 1012b, a shield layer 1012c, and a shield layer 1012d, respectively. The third cover plate 103 is provided with a second shielding layer 1032, and one or more second shielding layers 1032 are provided. Fig. 8 shows 4 second shield layers 1032,4 second shield layers 1032, which are a shield layer 1032a, a shield layer 1032b, a shield layer 1032c, and a shield layer 1032d, respectively.

The second cover plate 102 is provided with a third shielding layer 1022 and a fourth shielding layer 1023, one or more third shielding layers 1022 may be provided, and one or more fourth shielding layers 1023 may be provided. In fig. 8, 4 third shield layers 1022 and 4 fourth shield layers 1023,4 third shield layers 1022 are shown as shield layers 1022a, 1022b, 1022c, and 1022d, respectively, and 4 fourth shield layers 1023 are shown as shield layers 1023a, 1023b, 1023c, and 1023d, respectively.

The plurality of first shielding layers 1012 are opposite to the plurality of power units of the first layer 1001 one by one, and each power unit located in the first layer 1001 may be connected to a corresponding one of the first shielding layers 1012 through a wire.

As shown in fig. 8, wherein the shielding layer 1012a, the shielding layer 1012b, the shielding layer 1012c, and the shielding layer 1012d are all disposed in the top plate 1010 of the first cover plate and are spaced apart in the arrangement direction of the power cells 1 to 4. Power unit 1 is opposite to shield layer 1012a and connected by a wire, power unit 2 is opposite to shield layer 1012b and connected by a wire, power unit 3 is opposite to shield layer 1012c and connected by a wire, and power unit 4 is opposite to shield layer 1012d and connected by a wire.

It should be noted that the number of the first shielding layers 1012 and the number of the power units of the first layer 1001 are plural, and the number is equal. When the power units of the first shielding layer 1012 and the first layer 1001 in the first cover plate 101 are one, then the first shielding layer 1012 may be directly opposite to and connected with the power units of the first layer 1001. When the number of the first shielding layers 1012 in the first cover plate 101 is one and the number of the power cells of the first layer 1001 is plural, the first shielding layers 1012 may be opposed to and connected to any one of the power cells of the first layer 1001, may be opposed to and connected to any two or more of the power cells of the first layer 1001, or the first shielding layers 1012 may be opposed to and connected to all of the power cells of the first layer 1001. For example, the length of the first shielding layer 1012 may be equal to the total length of all the power cells of the first layer 1001 in the arrangement direction, so that the first shielding layer 1012 may be opposite to and connected with all the power cells of the first layer 1001, thereby ensuring that the first shielding layer 1012 can play a shielding effect on all the power cells of the first layer 1001. When the first shielding layer 1012 in the first cover plate 101 is a plurality of and the power unit of the first layer 1001 is one, then the power unit of the first layer 1001 may be opposite to and connected with any one or a plurality of the first shielding layers 1012. When the number of the first shielding layers 1012 in the first cover plate 101 and the number of the power units of the first layer 1001 are all plural, and the number of the plurality of the first shielding layers 1012 is not equal to the number of the plurality of the power units of the first layer 1001, if the number of the plurality of the first shielding layers 1012 is larger than the number of the plurality of the power units of the first layer 1001, each of the power units may be opposite to and connected with one of the first shielding layers 1012 in a part of the power units in the first layer 1001, and another part of the power units in the first layer 1001 may be opposite to and connected with two or more of the first shielding layers 1012. If the number of power cells of the first layer 1001 is greater than the number of first shield layers 1012, each first shield layer 1012 may be opposite and connected to one power cell in one portion of the first shield layers 1012, and each first shield layer 1012 may be opposite and connected to two or more power cells in another portion of the first shield layers 1012. The third cover plate 103 may have a plurality of second shielding layers 1032 disposed therein, the plurality of second shielding layers 1032 are opposite to the plurality of power cells of the second layer 1002 one by one, and each power cell located in the second layer 1002 is connected to one of the second shielding layers 1032 by a lead.

Referring next to fig. 8, shield layers 1032a, 1032b, 1032c, and 1032d are each disposed in the bottom plate 1030 of the third cover plate and are spaced apart in the arrangement direction of the power cells 8 to 5. The power unit 5 is opposite to the shield layer 1032d and connected by a wire, the power unit 6 is opposite to the shield layer 1032c and connected by a wire, the power unit 7 is opposite to the shield layer 1032b and connected by a wire, and the power unit 8 is opposite to the shield layer 1032a and connected by a wire.

Similarly, the number of the second shielding layers 1032 and the number of the power cells of the second layer 1002 are plural, and the number is equal. When the power units of the second shielding layer 1032 and the second layer 1002 in the third cover 103 are one, then the second shielding layer 1032 may be directly opposite to and connected with the power units of the second layer 1002. When the second shielding layer 1032 in the third cover plate 103 is one and the number of power cells of the second layer 1002 is plural, the second shielding layer 1032 may be opposite to and connected to any one of the power cells of the second layer 1002, may be opposite to and connected to any two or more of the power cells of the second layer 1002, or the second shielding layer 1032 may be opposite to and connected to all the power cells of the second layer 1002. For example, the length of the second shielding layer 1032 may be equal to the total length of all the power cells of the second layer 1002 in the arrangement direction, so that the 1012 of the first shielding layer may be opposite to and connected with all the power cells of the second layer 1002, thereby ensuring that the 1012 of the first shielding layer can play a shielding role on all the power cells of the second layer 1002. When the second shielding layer 1032 in the third cover plate 103 is a plurality of and the power unit of the second layer 1002 is one, then the power unit of the second layer 1002 may be opposite to and connected with any one or more of the second shielding layers 1032. When the number of the second shielding layers 1032 and the number of the power cells of the second layer 1002 in the third cover 103 are both plural, and the number of the plurality of the second shielding layers 1032 is not equal to the number of the plurality of the power cells of the second layer 1002, if the number of the plurality of the second shielding layers 1032 is larger than the number of the plurality of the power cells of the second layer 1002, each of the power cells may be opposite to and connected to one of the second shielding layers 1032 in a part of the power cells in the second layer 1002, and another part of the power cells in the second layer 1002 may be opposite to and connected to two or more of the second shielding layers 1032. If the number of power cells of the second layer 1002 is greater than the number of second shield layers 1032, each second shield layer 1032 may be opposite and connected to one power cell in one portion of the second shield layers 1032, and each second shield layer 1032 may be opposite and connected to two or more power cells in another portion of the second shield layers 1032.

Therefore, the conducting layers on the outer sides of the first cover plate and the third cover plate can be used as grounding plates, the shielding layers are arranged in the first cover plate and the third cover plate, and the power units and the shielding layers are connected through the leads, wherein the leads can conduct the power units and the shielding layers, and insulating materials are filled between the shielding layers and the conducting layers, so that the insulating performance is improved, and the power units and the grounding plates are prevented from being ignited due to the fact that air breaks down by higher voltage.

The second cover plate 102 may have a plurality of third shielding layers 1022 disposed therein, and as shown in fig. 8, the third shielding layers 1022 are located under the power cells of the first layer 1001. It will be appreciated that after the power module in fig. 8 is flipped upside down, the third shielding layer 1022 is located above the power cells of the first layer 1001. The plurality of power cells located at the first layer are in one-to-one correspondence with the plurality of third shielding layers 1022, and each power cell located at the first layer is connected to one of the third shielding layers 1022 through a lead.

As shown in fig. 8, the shielding layers 1022a, 1022b, 1022c, and 1022d are disposed in the intermediate plate 1020 of the second cover plate, and are spaced apart in the arrangement direction of the power cells 1 to 4. Wherein power unit 1 is opposite to shield layer 1022a and connected by a wire, power unit 2 is opposite to shield layer 1022b and connected by a wire, power unit 3 is opposite to shield layer 1022c and connected by a wire, and power unit 4 is opposite to shield layer 1022d and connected by a wire.

Similarly, the number of the third shielding layers 1022 and the number of the power cells of the first layer 1001 are plural, and the number is equal. For the scheme in which the number of third shielding layers 1022 is different from the number of power units of the first layer 1001, or the number of any one of the third shielding layers 1022 and the power units of the first layer 1001 is one, the connection scheme of the third shielding layers 1022 and the power units of the first layer 1001 is similar to the connection scheme of the first shielding layers 1012 and the power units of the first layer 1001, and will not be repeated here.

Thus, by providing the third shielding layer 1022 in the second cover 102 and conducting the power cells and the third shielding layer 1022 through the leads, it is possible to prevent breakdown between adjacent first-layer power cells and the second cover 102 due to the presence of an air gap, and to improve insulation performance between the first-layer power cells and the second-layer power cells.

A plurality of fourth shielding layers 1023 may be further disposed in the second cover plate, and as shown in fig. 8, the fourth shielding layers 1023 are located above the power cells of the second layer and below the third shielding layers 1022. It can be appreciated that the fourth shielding layer 1023 is located below the power cells of the second layer and above the third shielding layer after the power module in fig. 8 is flipped upside down. The power units located on the second layer are opposite to the fourth shielding layers 1023 one by one, and each power unit located on the second layer is connected with one fourth shielding layer 1023 through a lead.

Referring next to fig. 8, shielding layers 1023a, 1023b, 1023c, and 1023d are disposed in the intermediate plate 1020 of the second cover plate 102 and are spaced apart in the arrangement direction of the power cells 8 to 5. The power unit 5 is opposite to the shielding layer 1023d and connected by a wire, the power unit 6 is opposite to the shielding layer 1023c and connected by a wire, the power unit 7 is opposite to the shielding layer 1023b and connected by a wire, and the power unit 8 is opposite to the shielding layer 1023a and connected by a wire.

Similarly, the number of fourth shielding layers 1023 and the number of power cells of second layer 1002 are plural, and the number is equal. For the scheme in which the number of fourth shielding layers 1023 is different from the number of power units of the second layer 1002 or any one of the number of fourth shielding layers 1023 and the number of power units of the second layer 1002 is one, the connection scheme of the fourth shielding layers 1023 and the power units of the second layer 1002 is similar to the connection scheme of the second shielding layers 1032 and the power units of the second layer 1002, and will not be described here again.

Thus, by providing the fourth shielding layer 1023 in the second cover plate 102 and conducting the power cells and the fourth shielding layer 1023 through the leads, it is possible to prevent breakdown between the adjacent second-layer power cells and second cover plates due to the presence of an air gap, and to improve the insulation performance between the first-layer power cells and the second-layer power cells.

As shown in fig. 9, taking power unit n and power unit n+1 as an example, the O point of power unit n is connected to first shielding layer 1012 and third shielding layer 1022 through leads, respectively, and the O point of power unit n+1 is connected to fourth shielding layer 1023 and second shielding layer 1032 through leads, respectively.

Fig. 10 is an equivalent circuit diagram of power cell n and power cell n+1 in fig. 9, wherein point O is the capacitance midpoint, or bus midpoint, of power cell n and power cell n+1, respectively. The O-point potential is equal to the potentials at the fourth shield layer 1023 and the third shield layer 1022.

Therefore, the shielding layer is arranged in the cover plate, the power unit is connected with the shielding layer through the lead, the power unit is directly conducted with the shielding layer, the potential on the shielding layer is equal to that of the power unit, the shielding layer and the grounding plate are filled with insulating materials, and discharge caused by an air gap between the power unit and the conducting layer is avoided.

As shown in fig. 8 and 11, the first connecting plate 1011 is located between the top plate 1010 and the middle plate 1020 of the second cover plate 102. Similarly, a fifth shielding layer 10110 is disposed in the first connection board 1011, and the fifth shielding layer 10110 is opposite to and connected with one or more power units located on the first layer 1001. The fifth shielding layer 10110 may also be one or more. Fig. 8 shows two fifth shielding layers 10110, where two fifth shielding layers 10110 are respectively located in two first connection plates 1011, one fifth shielding layer 10110 is opposite to and connected with the power unit 1, and the other fifth shielding layer 10110 is opposite to and connected with the power unit 4.

Thus, by providing the fifth shielding layer 10110 in the first connection plate 1011 and conducting the power cells and the fifth shielding layer 10110 through the leads, it is possible to prevent breakdown between adjacent first-layer power cells and the first connection plate 1011 due to the presence of an air gap, further improving insulation performance between the first-layer power cells and the second-layer power cells.

As shown in fig. 8 and 11, the third connecting plate 1031 is located between the base plate 1030 and the middle plate 1020 of the second cover plate 102. Similarly, a sixth shielding layer 10310 is disposed in the third connection board 1031, and the sixth shielding layer 10310 is opposite to and connected with one or more power cells located on the second layer 1002. The sixth shielding layer 10310 may also be one or more. Fig. 8 shows two sixth shielding layers 10310, where two sixth shielding layers 10310 are respectively located in two third connection plates 1031, one sixth shielding layer 10310 is opposite to and connected with the power unit 8, and the other sixth shielding layer 10310 is opposite to and connected with the power unit 5.

Thus, by providing the sixth shielding layer 10310 in the third connection plate 1031 and conducting the power cells and the sixth shielding layer 10310 through the leads, it is possible to prevent breakdown between the adjacent second-layer power cells and the third connection plate 1031 due to the presence of the air gap, further improving the insulation performance between the first-layer power cells and the second-layer power cells.

The structure of the fifth shielding layer 10110 and the sixth shielding layer 10310 is not limited in the embodiment of the application, wherein the fifth shielding layer 10110 may be integrally formed with the first shielding layer 1012. The sixth shielding layer 10310 may be integrally formed with the fifth shielding layer 10110.

Based on the above, in the embodiment of the present application, the first connection plate 1011 and the third connection plate 1031 are opposite, and the first gap 106 is provided between the first connection plate 1011 and the third connection plate 1031. Thus, no shielding layer is provided at the first slit 106, so that the first slit 106 may act as an electrical gap, where an electric field may be generated.

The second connection plate 1021 is located inside the first connection plate 1011 and the third connection plate 1031, and a second gap 107 is provided between the second connection plate 1021 and the first connection plate 1011, a third gap 108 is provided between the second connection plate 1021 and the third connection plate 1031, and the first gap 106, the second gap 107, and the third gap 108 are communicated. And, the second connection plate 1021 has a gap with the top plate 1010 and the bottom plate 1030.

The creepage paths (electric gaps) of the first slit 106, the second slit 107, and the third slit 108 are as shown by arrows in fig. 11, respectively, started from the third shielding layer 1022, the fourth shielding layer 1024, and wound around the surface of the second connection board 1021, and then led to the first slit 106 from the second slit 107, the third slit 108, respectively.

From this, second connecting plate 1021, first connecting plate 1011 and third connecting plate 1031 constitute the fold structure, and insulating material leaves first gap 106 from top to bottom butt-joint department, is equipped with second gap 107 and third gap 108 between second connecting plate 1021, first connecting plate 1011 and the third connecting plate 1031, and this first gap 106, second gap 107 and third gap 108 are as the electric gap, can increase the creepage distance between shielding layer and the conducting layer, reduces electric field strength.

It should be noted that the electrical gap refers to the shortest spatial distance measured between two conductive parts or between a conductive part and a device protection interface. Creepage distance refers to the shortest path between two conductive parts or between a conductive part and a device protection interface measured along an insulating surface.

As shown in fig. 11, an end of the first connecting plate 1011 near the third connecting plate 1031 is chamfered (at a junction between the first gap 106 and the second gap 107). The chamfer can be a circular arc chamfer or a rectangular chamfer. Thereby, the width of the first gap 106 between the first connection plate 1011 and the third connection plate 1031 can be increased, the electric gap can be increased, and the electric field intensity can be reduced.

One end of the third connecting plate 1031 near the first connecting plate 1011 is chamfered (at the junction of the first gap 106 and the third gap 108). The chamfer can be a circular arc chamfer or a rectangular chamfer. Thereby, the width of the first gap 106 between the first connection plate 1011 and the third connection plate 1031 can be increased, the electric gap can be increased, and the electric field intensity can be reduced.

The second connection plate 1021 is chamfered at a side close to the first connection plate 1011 and the third connection plate 1031. I.e., the chamfer is formed at the intersection of the top surface of the second connection plate 1021 and the side surface near the first connection plate 1011, and the intersection of the bottom surface of the second connection plate 1021 and the side surface near the first connection plate 1011. The chamfer can be a circular arc chamfer or a rectangular chamfer. Thus, the widths of the second slit 107 and the third slit 108 can be increased at the same time, the electric gap can be increased, and the electric field strength can be reduced. For example, the top surface and the bottom surface of the second connecting plate 1021 can also directly adopt arc surfaces, so that the manufacturing is convenient.

Referring to fig. 11, arc angles of the connection plates surrounding the first, second and third slits 106, 107 and 108 are processed, so that the width of the slits is increased, and the air electric field intensity of the slits at the butt-joint position can be reduced.

In addition, as shown in fig. 12 and 13, the power module 10 further includes a housing 105, the housing 105 being disposed and connected to the outside of the housing 100, the housing 105 being capable of protecting the power module 10.

The housing 105 includes at least an upper shell 1051 and a lower shell 1052, wherein the upper shell 1051 is disposed outside the first cover plate 101 and is detachably connected to the first cover plate 101, the lower shell 1052 is disposed outside the third cover plate 103 and is detachably connected to the third cover plate 103, and the upper shell 1051 and the lower shell 1052 are detachably connected.

The material of the housing 105 is not limited in the embodiments of the present application, and in some embodiments, the housing is made of metal, for example. The heat dissipation performance is better, and the stability is higher.

The housing 105 further includes a front housing 1053 and a rear housing 1054, and the front housing 1053 is provided with a heat dissipation structure, whereby the heat dissipation performance of the power module can be improved. A single board is provided on the rear housing 1054.

The foregoing is merely illustrative of specific embodiments of the present application, and the scope of the present application is not limited thereto, but any changes or substitutions within the technical scope of the present application should be covered by the scope of the present application. Therefore, the protection scope of the present application shall be subject to the protection scope of the claims.

Claims

1. A power module, comprising: a housing and a plurality of power units;

The plurality of power units are spatially divided into a first layer and a second layer, each layer including at least one of the power units;

The housing comprises: a first cover plate, a second cover plate and a third cover plate which are stacked, wherein the second cover plate is located between the first cover plate and the third cover plate, wherein a first layer of power units is arranged on a side of the first cover plate close to the second cover plate, and a second layer of power units is arranged on a side of the third cover plate close to the second cover plate;

The first cover plate comprises: a top plate and a first connecting plate connected to each other, and the third cover plate comprises a bottom plate and a third connecting plate connected to each other, the top plate is arranged opposite to the bottom plate, the first connecting plate is located between the top plate and the second cover plate, the third connecting plate is located between the bottom plate and the second cover plate, the first connecting plate and the third connecting plate are opposite to each other, and there is a gap between the first connecting plate and the third connecting plate;

The second cover plate includes: a middle plate and a second connecting plate, the middle plate is opposite to the top plate and the bottom plate respectively; the second connecting plate is located on the inner side of the first connecting plate and the third connecting plate, wherein there is a gap between the second connecting plate and the first connecting plate, and there is a gap between the second connecting plate and the third connecting plate.

2. The power module according to claim 1 is characterized in that each of the first layer and the second layer comprises a plurality of the power units, all the power units in the same layer are connected in series in sequence, and a power unit located at the end of the first layer and a power unit located at the end of the second layer are connected in series.

3 . The power module according to claim 1 , wherein the first cover plate, the second cover plate and the third cover plate are all made of insulating material.

4. The power module according to claim 3, characterized in that a conductive layer is provided on the outer sides of the first cover plate and the third cover plate, at least one first shielding layer is provided in the first cover plate, the at least one first shielding layer is opposite to the at least one power unit located in the first layer one by one, and each power unit located in the first layer is electrically connected to the corresponding at least one first shielding layer;

At least one second shielding layer is disposed in the third cover plate, and the at least one second shielding layer is opposite to the at least one power unit located in the second layer one by one, and each power unit located in the second layer is electrically connected to the corresponding at least one second shielding layer.

5. The power module according to claim 3 or 4 is characterized in that at least one third shielding layer is provided in the second cover plate, the at least one third shielding layer is located below the power unit of the first layer, the at least one third shielding layer is opposite to the at least one power unit located on the first layer one by one, and each power unit located on the first layer is electrically connected to the corresponding at least one third shielding layer.

6. The power module according to any one of claims 3-5 is characterized in that at least one fourth shielding layer is provided in the second cover plate, the at least one fourth shielding layer is located above the power unit of the second layer and below the third shielding layer, the at least one fourth shielding layer is opposite to the at least one power unit located on the second layer one by one, and each power unit located on the second layer is electrically connected to the corresponding at least one fourth shielding layer.

7 . The power module according to claim 1 , wherein a fifth shielding layer is provided in the first connecting plate, and the fifth shielding layer is opposite to at least one of the power units located on the first layer and is electrically connected to each other.

8. The power module according to any one of claims 1 to 6, characterized in that a sixth shielding layer is provided in the third connecting plate, and the sixth shielding layer is opposite to at least one of the power units located on the second layer and is electrically connected to each other.

9 . The power module according to claim 1 , wherein an end of the first connecting plate close to the third connecting plate is chamfered.

10 . The power module according to claim 1 , wherein an end of the second connecting plate close to the first connecting plate and the third connecting plate is chamfered.

11 . The power module according to claim 1 , wherein a side of the third connecting plate close to the first connecting plate is chamfered.

12. The power module according to any one of claims 1-10, characterized in that positioning posts are provided on the first cover plate and the third cover plate, and positioning holes are provided on the second cover plate, the positioning posts are opposite to the positioning holes one by one, and the positioning posts are inserted into the positioning holes.

13 . The power module according to claim 1 , further comprising a housing, wherein the housing is arranged around the shell and connected to the shell.

14 . The power module according to claim 13 , wherein the housing is made of metal.

15 . The power module according to claim 13 , wherein the housing is provided with heat dissipation holes.

16. A power supply system, characterized in that the power supply system comprises a power supply and a power module according to any one of claims 1 to 15, wherein the power supply is connected to an input terminal of the power module.