Protective structure for MMC sub-module and MMC sub-module

Abstract

The invention provides a protection structure for an MMC sub-module and the MMC sub-module, the MMC sub-module comprises a capacitor assembly and a power module located at one side of the capacitor assembly, and the capacitor assembly and the power module are connected through an arranged laminated busbar assembly; the protection structure comprises a plurality of through holes arranged on the inner layer of the laminated busbar assembly, the plurality of through holes are distributed to form a strip-shaped area, and the strip-shaped area is located at the boundary of the capacitor assembly and the power module. Through the arrangement, when explosion occurs in the power module, the inner layer of the laminated busbar assembly impacted by the explosion is easy to break in the strip-shaped area by means of the plurality of through holes in the inner layer of the laminated busbar assembly, so that the power module can quickly cut off the electric connection with the capacitor assembly at the first time of explosion; and meanwhile, the inner layer of the laminated busbar assembly is disconnected in advance, so that the electrode of the capacitor assembly can be prevented from being rigidly stretched on the inner side, the integrity of capacitor connection on one side of the capacitor assembly is ensured, and the safety protection performance of the MMC sub-module under the explosion working condition is integrally improved.

Description

Technical Field

[0001] This invention relates to the field of flexible DC transmission technology, specifically providing a protective structure for an MMC submodule and an MMC submodule. Background Technology

[0002] In flexible DC transmission projects, voltage source converter technology, represented by modular multilevel converters (MMCs), achieves AC-DC conversion through cascaded submodules. MMC submodules typically consist of capacitor banks, power modules (such as IGBTs), and connecting busbars. Their modular design offers significant advantages in scenarios such as renewable energy grid integration and long-distance power transmission.

[0003] In existing MMC submodules, the capacitor assembly and power module are directly connected via a rigid capacitor busbar. When an explosion occurs inside the submodule, the rigid capacitor busbar cannot quickly cut off the discharge circuit of the capacitor assembly, causing the capacitor assembly to remain energized and forming an "energy channel" for fire spread. Furthermore, the capacitor that is not de-energized may ignite surrounding equipment or leak electrolyte, causing secondary disasters. At the same time, the residual voltage poses a direct electric shock threat to subsequent maintenance personnel, increasing the difficulty of subsequent handling.

[0004] In summary, the existing MMC submodules have poor safety protection performance under explosive conditions. Summary of the Invention

[0005] The purpose of this invention is to address the problem of poor safety protection performance of existing MMC submodules under explosive conditions.

[0006] The objective of this invention is achieved through the following technical solution: This invention provides a protective structure for an MMC submodule, the MMC submodule including a capacitor assembly and a power module located on one side of the capacitor assembly, the capacitor assembly and the power module being connected by a stacked busbar assembly; the protective structure includes a plurality of through holes disposed on the inner layer of the stacked busbar assembly, the plurality of through holes being distributed to form a strip-shaped area, the strip-shaped area being located at the junction of the capacitor assembly and the power module.

[0007] Preferably, the strip-shaped region is any one of straight strip, curved strip, arc, and serrated.

[0008] Preferably, the through hole is any one of a circular hole, a star-shaped hole, and a polygonal hole.

[0009] Preferably, the through hole is a variable diameter hole, and the opening of the variable diameter hole is disposed facing the outer layer side of the stacked busbar assembly.

[0010] Preferably, the stacked busbar assembly includes an inner positive busbar and an outer negative busbar, and the protective structure further includes a linear groove disposed on the surface of the positive busbar, wherein the linear groove is connected in series with at least two of the through holes.

[0011] Preferably, the through holes are located in the current-dense area of ​​the inner layer of the stacked busbar assembly and are evenly distributed.

[0012] Preferably, the protective structure further includes an explosion-proof housing, which is fixed to the outside of the capacitor assembly and the power module. The explosion-proof housing has a pressure relief area formed by a combination of multiple mesh holes, and the pressure relief area is located on the side of the power module.

[0013] Preferably, the protective structure further includes a first explosion-proof plate, which is disposed between the capacitor assembly and the explosion-proof housing, and the first explosion-proof plate and the explosion-proof housing located on the side of the power module combine to form a protective space.

[0014] Preferably, the protective structure further includes a second explosion-proof plate, which is located between the stacked busbar assembly and the explosion-proof housing, and is fixed to the power module and / or the capacitor assembly.

[0015] Preferably, the power module includes a support frame, a power device, a heat sink, and a water inlet pipe. The power device and the heat sink are press-fitted and fixed on the support frame. The heat sink is sleeved and fixed on the outside of the power device. The water inlet pipe is connected to the water passage inside the heat sink. The protective structure also includes a blocking member fixed on the heat sink. The blocking member is adapted to block the water inlet pipe located in the peripheral space of the power device.

[0016] Preferably, the water inlet pipe includes an outer water inlet pipe exposed to the outside, and the blocking member is fixed to the outside of the radiator with an explosion-proof block to shield the outer water inlet pipe.

[0017] Preferably, the water inlet pipe further includes an inner water inlet pipe located inside, and the blocking member is a strip-shaped member embedded and fixed in the interval space of the radiator to block the inner water inlet pipe.

[0018] Preferably, the protective structure further includes an anti-pressure block, which is arranged along the pressing direction of the radiator.

[0019] Preferably, the anti-pressure block is made of insulating material and the surface of the anti-pressure block is provided with anti-creep grooves, which are arranged opposite to the space between the anti-creep grooves and the heat sink.

[0020] Based on the same inventive concept, the present invention also provides an MMC submodule, which adopts the protective structure of the MMC submodule.

[0021] Compared with the prior art, the beneficial effects of the present invention are as follows: This invention provides a protective structure for an MMC submodule. The MMC submodule includes a capacitor assembly and a power module located on one side of the capacitor assembly. The capacitor assembly and the power module are connected by a stacked busbar assembly. The protective structure includes multiple through holes on the inner layer of the stacked busbar assembly, which are distributed to form a strip-shaped area located at the boundary between the capacitor assembly and the power module. With this design, when an explosion impacts the stacked busbar assembly within the power module, the multiple through holes on the inner layer of the stacked busbar assembly allow the inner layer to easily break in the strip-shaped area. This enables the power module to quickly disconnect its electrical connection with the capacitor assembly at the boundary immediately after the explosion. Furthermore, when the explosion energy is too high, the initial disconnection of the inner layer of the stacked busbar assembly prevents the stacked busbar assembly from rigidly stretching the electrodes of the capacitor assembly on its inner side, ensuring the integrity of the capacitor connection on the capacitor assembly side. Overall, this improves the safety protection performance of the MMC submodule under explosive conditions. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the overall structure of the MMC submodule in Embodiment 1 of the present invention; Figure 2 This is a schematic diagram of the internal structure of the MMC submodule in Embodiment 1 of the present invention; Figure 3 This is a schematic diagram of the assembly of the stacked busbar and heat sink of the MMC submodule in Embodiment 1 of the present invention; Figure 4 This is a schematic diagram showing the through-hole structure distribution of the positive busbar of the MMC submodule in Embodiment 1 of the present invention; Figure 5 This is a schematic diagram of the through-hole structure distribution of the positive busbar of the MMC submodule in Embodiment 2 of the present invention; Figure 6 This is a schematic diagram of the through-hole structure distribution of the positive busbar of the MMC submodule in Embodiment 3 of the present invention; Figure 7 This is a cross-sectional schematic diagram of the through-hole structure of the positive busbar of the MMC submodule in Embodiment 4 of the present invention; Figure 8 This is a schematic diagram of the through-hole distribution of the positive busbar of the MMC submodule in Embodiment 5 of the present invention; Figure 9 This is a schematic diagram showing the position of the first explosion-proof plate of the MMC submodule in Embodiment 1 of the present invention; Figure 10 This is a schematic diagram of the assembly of the strip and the heat sink of the MMC submodule in Embodiment 1 of the present invention; Figure 11This is a schematic diagram of the assembly of the anti-pressure block and the heat sink of the MMC submodule in Embodiment 1 of the present invention.

[0023] Reference numerals: 1-Capacitor assembly; 11-Positive busbar; 111-Through hole; 112-Linear groove; 12-Negative busbar; 2-Power module; 20-Main support frame; 21-Power device; 22-Heat sink; 23-Pressure frame; 231-Clamping plate; 232-Connecting rod; 24-Explosion-proof block; 25-Strip piece; 26-Anti-pressure block; 261-Anti-creep groove; 27-First explosion-proof plate; 28-Second explosion-proof plate; 3-Mounting base; 4-Explosion-proof housing; 41-First housing; 42-Second housing; 5-Outer water pipe; 6-External positive and negative busbars; 7-Screw. Detailed Implementation

[0024] Preferred embodiments of the present invention will now be described with reference to the accompanying drawings. Those skilled in the art should understand that these embodiments are merely illustrative of the technical principles of the invention and are not intended to limit the scope of protection of the invention. Those skilled in the art can make adjustments as needed to adapt to specific applications.

[0025] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0026] It should be noted that in the description of this invention, terms such as "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," indicating directional or positional relationships, are based on the directional or positional relationships shown in the accompanying drawings. These are merely for ease of description and do not indicate or imply that the device or element must have a specific orientation, or be constructed and operated in a specific orientation; therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0027] Example 1 like Figures 1 to 4As shown, this embodiment provides a protective structure for an MMC submodule. The MMC submodule includes a capacitor assembly 1, a power module 2, and a mounting base 3. The power module 2 is located on one side of the capacitor assembly 1, meaning that the capacitor assembly 1 and the power module 2 are mounted front-to-back along the length of the mounting base 3. The capacitor assembly 1 and the power module 2 are connected by a stacked busbar assembly, which includes an inner positive busbar 11 and an outer negative busbar 12.

[0028] Specifically, such as Figure 2 and Figure 3 As shown, capacitor assembly 1 includes three capacitors connected in parallel. Specifically, the positive electrodes of all three capacitors are fixedly connected to the main body of the positive busbar 11, and the negative electrodes of all three capacitors are fixedly connected to the main body of the negative busbar 12. The leads of the positive busbar 11 and the negative busbar 12 extend into the functional module for fixation.

[0029] like Figure 4 As shown, the protective structure of this embodiment includes multiple through holes 111 disposed on the positive busbar 11. The multiple through holes 111 are distributed to form a strip-shaped area, which is located at the junction of the capacitor assembly 1 and the power module 2. The strip-shaped area is straight, and the through holes 111 are circular holes with a diameter ranging from 1mm to 5mm.

[0030] When an explosion occurs within power module 2, the laminated busbar assembly is subjected to the explosive impact. Its inner positive busbar 11 is equipped with a fracture protection measure consisting of a strip area of ​​through holes 111. The high-voltage positive busbar 11 can be disconnected immediately upon explosion, achieving rapid power disconnection between power module 2 and capacitor assembly 1. When the explosion energy is too large, the prior disconnection of the positive busbar 11 also prevents rigid stretching of the positive busbar 11 against the electrodes of capacitor assembly 1, ensuring the integrity of the capacitor connection on one side of capacitor assembly 1 and reducing the difficulty of subsequent maintenance. Furthermore, by utilizing the structural space at the junction of capacitor assembly 1 and power module 2, the structural interference between the main body and the leads of the positive busbar 11 after disconnection is reduced, avoiding the risk of reconnection between the main body and the leads after the positive busbar 11 is disconnected.

[0031] It should be noted that, in a preferred embodiment, the multiple through holes 111 are located in the current-dense area of ​​the positive busbar 11 and are evenly distributed.

[0032] This design serves two purposes: firstly, it avoids uneven heat distribution in the positive busbar 11 due to uneven distribution of the through-hole 111 structure, ensuring the normal operation of the positive busbar 11 circuit; secondly, under explosive conditions, it ensures that the positive busbar 11 is evenly and neatly disconnected along the strip area, avoiding the risk of incomplete disconnection in some areas when the explosive force is small.

[0033] The protective structure of the present invention also includes an explosion-proof housing 4, which is fixed on the outside of the capacitor assembly 1 and the power module 2. The explosion-proof housing 4 is provided with a pressure relief area formed by a combination of multiple mesh holes, and the pressure relief area is located on one side of the power module 2.

[0034] Specifically, such as Figure 1 As shown, the explosion-proof housing 4 in this embodiment includes a first housing 41 and a second housing 42. The first housing 41 is fixed to one side of the capacitor electrode and covers the main body of the connected capacitor electrode and the stacked busbar assembly. The second housing 42 is fixed to the outside of the functional module and covers the top and sides of the functional module.

[0035] Among them, on the side of the functional module, the left and right side plates of the second outer shell 42 are provided with a honeycomb-shaped pressure relief area formed by a combination of multiple mesh holes, and the front side plate of the second outer shell 42 is provided with a pressure relief area formed by a combination of multiple mesh holes of different diameters.

[0036] With this configuration, the second housing 42 can intercept the explosive fragments of the power module 2 to prevent them from scattering to the outside world and causing pollution to the adjacent area. At the same time, the second housing 42 can offset part of the explosive energy and mitigate / reduce the spillover of the explosive impact.

[0037] like Figure 3 As shown, the power module 2 in this embodiment includes a support frame, a power device 21, a heat sink 22, and a water pipe. The power device 21 and the heat sink 22 are both press-fitted and fixed on the support frame. The heat sink 22 is sleeved and fixed on the outside of the power device 21. The water pipe is connected to the water passage inside the heat sink 22.

[0038] Specifically, the support frame includes a main support frame 20 and a press-fit frame 23 installed inside the main support frame 20. The main support frame 20 is fixed on the mounting base 3. The press-fit frame 23 includes two clamping plates 231 and four connecting rods 232. The power device 21 and the heat sink 22 are installed between the two clamping plates 231 and press-fitted by tightening the connecting rods 232.

[0039] like Figure 9 As shown, the protective structure of this embodiment also includes a first explosion-proof plate 27. The first explosion-proof plate 27 is disposed at the junction of the capacitor assembly 1 and the power module 2. The first explosion-proof plate 27 and the second shell 42 are combined to form a semi-enclosed protective space to cover the power module 2, so as to prevent the power module 2 from impacting one side of the capacitor assembly 1 when it explodes. The first explosion-proof plate 27 is fixed on the main support frame 20 and the mounting base 3.

[0040] It should be noted that, depending on the actual application, those skilled in the art may also set the first explosion-proof plate 27 between adjacent capacitors, or the first explosion-proof plate 27 may be set at the rear end of the capacitor assembly 1.

[0041] like Figures 1 to 3 As shown, the protective structure of this embodiment also includes a second explosion-proof plate 28, which is located between the top surface of the stacked busbar assembly and the explosion-proof housing 4, and is fixed to the power module 2 and / or capacitor assembly 1.

[0042] Specifically, in this embodiment, one side of the second explosion-proof plate 28 is fixed to the main support frame 20, and the other side is fixed to a preset mounting position on the capacitor. The second explosion-proof plate 28 shields the negative busbar 12 of the laminated busbar at the junction. Under explosion conditions, when the positive busbar 11 is broken by force, it prevents the explosive impact from breaking the negative busbar 12, ensuring the integrity of the laminated busbar structure, ensuring the connection between the negative busbar 12 and the ground, and reducing the safety of subsequent maintenance.

[0043] It should be noted that, depending on the actual application, those skilled in the art can fix the second explosion-proof plate 28 to the capacitor assembly 1, or it can be directly fixed to the main support frame 20.

[0044] like Figure 3 As shown, in this embodiment, the leads of the positive busbar 11 and the negative busbar 12 are fixed relative to each other inside the two spaced heat sinks 22 by screws 7. This generates a repulsive electrodynamic force between the leads of the positive busbar 11 and the negative busbar 12, which is in the same direction as the tightening of the screws 7. This reduces the reverse force on the screws 7 and enhances the tightness between the leads of the laminated busbar assembly and the heat sinks 22. Furthermore, the repulsive electrodynamic force between the leads of the laminated busbar assembly is absorbed by the heat sinks 22, which can also effectively reduce the impact on the laminated busbar assembly during an explosion.

[0045] like Figure 3 , Figure 10 and Figure 3 As shown, the protective structure of this embodiment also includes a blocking member fixed on the radiator 22. The blocking member is adapted to the water pipe located in the peripheral space of the power device 21 to block the explosives of the power device 21 from splashing toward the water pipe.

[0046] Specifically, the radiator 22 is connected to the water circuit via a water inlet pipe, which is inevitably exposed in the peripheral space of the power device 21. The water inlet pipe includes an outer water inlet pipe 5 exposed to the outside, and an explosion-proof block 24 is used to shield the outer water inlet pipe 5 between the power device 21.

[0047] like Figure 3 and Figure 10 As shown, the outer water pipe 5 is located in the front area of ​​the power module 2, and the blocking component is installed on the front of the heat sink 22 and blocks the power device 21 exposed between the heat sinks 22.

[0048] like Figure 11As shown, the water inlet pipe also includes an inner water inlet pipe (not shown in the figure) located inside, and the blocking strip 25 is embedded and fixed in the interval space of the radiator 22 to block the inner water inlet pipe.

[0049] In this embodiment, the strip 25 is curved along its length, and an installation end is provided in the middle of the curved arc to facilitate the fixing of the strip 25 to the heat sink 22.

[0050] With this design, the blocking component can shield the water pipe from flying debris from the power device 21 explosion, preventing it from being scratched or severed. This avoids leaks and short circuits, reducing the difficulty of subsequent maintenance. Replacing the water pipe requires shutting down the valve hall water pump, which is a significant workload. The blocking component is made of high-strength composite resin fiber material to embed and insulate against sharp fragments from the power device 21.

[0051] It should be noted that there are multiple blocking components. Depending on the actual application, those skilled in the art can increase or decrease the number of blocking components according to the specific water connection route of the water pipe and the position of the power device 21, thereby protecting the water pipe along the water path.

[0052] In addition, the heat sink 22 is made of aluminum alloy, and an external positive and negative busbar 612 is fixedly installed on the outside of the heat sink 22 to facilitate electrical connection with adjacent sub-modules.

[0053] like Figures 3 to 11 As shown, the protective structure in this embodiment also includes an anti-pressure block 26, which is arranged along the pressing direction of the radiator 22.

[0054] Before the power device 21 explodes, the difference in pressing force between the heat sink 22 and the power device 21 generates friction on their contact surfaces, which causes the heat sink 22 to shift at an angle, resulting in the heat sink 22 and the power device 21 becoming loose inside the pressing frame 23.

[0055] When a direct-through explosion occurs, the stress generated by the direct discharge of the capacitor causes the stacked busbar assembly to pull the radiator 22, which in turn causes the radiator 22 to undergo large deformation. Excessive deformation may cause the water pipe to break or the press-fit assembly to become insecure.

[0056] In this embodiment, anti-pressure blocks 26 are provided on the upper and lower sides of the radiator 22 and on the side connected to the stacked busbar. The anti-pressure blocks 26 are symmetrically arranged on the connecting rod 232.

[0057] By setting up the anti-pressure block 26, the angle of offset between the radiator 22 and the plane perpendicular to the pressing axis can not exceed 6 degrees and the displacement can not exceed 15 mm before and after the explosion occurs, thus ensuring the tightness and stability of the radiator 22 and the power device 21 inside the pressing frame 23.

[0058] The anti-pressure block 26 is made of insulating material, and the surface of the anti-pressure block 26 has anti-creep grooves 261, which are positioned opposite to the space between the anti-creep grooves 261 and the heat sink 22. The insulating material can be a high-strength resin material or bakelite material.

[0059] It should be noted that the anti-creep groove 261 is provided in the anti-creep block 26 to avoid potential problems between different heat sinks 22. The anti-creep groove 261 is designed with the required creepage distance calculated by multiplying the single-level voltage difference by the insulation creepage distance. In addition, the explosion-proof block also has an anti-creep groove design.

[0060] Example 2 The main difference between the protective structure in this embodiment and that in embodiment 1 is that the linear groove 112 on the surface of the positive busbar 11 in this embodiment is arranged opposite to the negative busbar 12, and the linear groove 112 has at least two through holes 111 connected in series.

[0061] like Figure 5 As shown, in this embodiment, the three linear grooves 112 connect the through holes 111. With this arrangement, the positive busbar 11 can be neatly disconnected in the event of an explosion, increasing the fragility of the positive busbar 11.

[0062] The other structures in this embodiment are the same as those in Embodiment 1, so they will not be described again here.

[0063] Example 3 like Figure 6 As shown, the main difference between the protective structure in this embodiment and that in Embodiment 1 is that the strip area in this embodiment is arc-shaped.

[0064] It should be noted that, depending on the actual application, the strip area can be set as a curved shape formed by connecting the ends of an S-shape or a U-shape, or as a sawtooth shape formed by connecting the ends of a Z-shape, so that those skilled in the art can make flexible adjustments according to different positive busbar 11 structures.

[0065] The other structures in this embodiment are the same as those in Embodiment 1, so they will not be described again here.

[0066] Example 4 The main difference between the protective structure in this embodiment and that in embodiment 1 is that the through hole 111 in this embodiment is a variable diameter hole, and the opening of the variable diameter hole is set towards the negative busbar 12.

[0067] by Figure 4 For reference, AA direction Figure 7The variable diameter hole in the busbar is designed with its opening facing upwards. By setting the variable diameter hole, the mechanical strength of the two sides of the positive busbar 11 is different, making the positive busbar 11 easier to disconnect under explosive conditions.

[0068] The other structures in this embodiment are the same as those in Embodiment 1, so they will not be described again here.

[0069] Example 5 like Figure 8 As shown, the main difference between the protective structure in this embodiment and that in Embodiment 1 is that the through hole 111 in this embodiment is a star-shaped hole with a four-star structure.

[0070] With this configuration, the star-shaped aperture can facilitate crack opening and reduce the breaking strength of the positive busbar 11. It should be noted that, depending on the specific application, those skilled in the art can also select a three-star structure, a five-star structure, or more than five-star structures for the star-shaped aperture.

[0071] In addition, depending on the actual application, the through hole 111 can also adopt various deformable structures such as triangle, rectangle, rhombus, etc., so that those skilled in the art can flexibly design and adjust it according to the different structural strengths of the positive busbar 11.

[0072] The other structures in this embodiment are the same as those in Embodiment 1, so they will not be described again here.

[0073] Example 6 like Figures 1 to 11 As shown, this embodiment provides an MMC submodule, which adopts any one of the protective structures for MMC submodules in embodiments 1-5.

[0074] The MMC submodule employing the above-described protective structure has the following effects: I. By setting through holes 111 on the positive busbar 11 to create a mechanical strength gradient, an explosion pressure release breakpoint is artificially established. When a submodule explodes, the busbar at the breakpoint breaks first, quickly cutting off the explosion energy transmission path and preventing the explosion's impact from spreading to other busbars, thus reducing the risk of system circuit failure from the source. II. Achieving dual protection functions of explosion-proof and impact release. II. The MMC sub-module features an explosion-proof system built around "system protection" as its core, through the synergistic effect of multi-dimensional protective components: Strengthening the fastening: Install a second explosion-proof plate 28 between the negative busbar 12 and the explosion-proof housing 4 to enhance the connection stability between the capacitor assembly 1 and the functional module under the impact of an explosion. Protection-Energy Release: The first explosion-proof plate 27 and the second outer shell 42 form a closed space to shield the functional module, thus constructing a "protection-energy release" collaborative mechanism: On the one hand, the semi-enclosed structure can effectively intercept the damaging materials generated by the explosion (such as metal splashes) and prevent them from flying to the outside of the sub-module to contaminate the valve tower or affect the electrical insulation; on the other hand, the pressure relief mesh can release the explosive impact energy in a directional manner to avoid secondary damage caused by energy accumulation.

[0075] Deformation-resistant supports: Anti-pressure blocks 26 are installed between the radiators 22 to resist structural torsion caused by explosive impact; Isolation and sealing: A blocking device is installed between the radiator 22 and the water pipe to shield the water pipe from direct impact and secondary damage caused by the explosion debris.

[0076] The aforementioned multi-dimensional protection structure significantly improves the overall safety protection effect of the MMC submodule under explosive conditions.

[0077] The above are merely embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention are included within the scope of the claims of the present invention pending approval.

Claims

1. A protective structure for an MMC submodule, characterized in that, The MMC submodule includes a capacitor assembly (1) and a power module (2) located on one side of the capacitor assembly (1). The capacitor assembly (1) and the power module (2) are connected by a stacked busbar assembly. The protective structure includes a plurality of through holes (111) disposed on the inner layer of the stacked busbar assembly. The plurality of through holes (111) are distributed to form a strip area, which is located at the junction of the capacitor assembly (1) and the power module (2).

2. The protective structure for MMC submodules according to claim 1, characterized in that, The strip-shaped area can be any one of the following: straight strip, curved strip, arc, or serrated.

3. The protective structure for MMC submodules according to claim 1, characterized in that, The through hole (111) can be any one of a circular hole, a star-shaped hole, or a polygonal hole.

4. The protective structure for MMC submodules according to claim 1, characterized in that, The through hole (111) is a variable diameter hole, and the opening of the variable diameter hole is set towards the outer side of the stacked busbar assembly.

5. The protective structure for MMC submodules according to claim 1, characterized in that, The stacked busbar assembly includes an inner positive busbar (11) and an outer negative busbar (12). The protective structure also includes a linear groove (112) disposed on the surface of the positive busbar (11), and the linear groove (112) is connected in series with at least two of the through holes (111).

6. The protective structure for an MMC submodule according to claim 1, characterized in that, The through-hole (111) is located in the current-dense area of ​​the inner layer of the stacked busbar assembly and is evenly distributed.

7. The protective structure for MMC submodules according to claim 1, characterized in that, The protective structure also includes an explosion-proof housing (4), which is fixed to the outside of the capacitor assembly (1) and the power module (2). The explosion-proof housing (4) is provided with a pressure relief area formed by a combination of multiple mesh holes, which is located on the side of the power module (2).

8. The protective structure for an MMC submodule according to claim 7, characterized in that, The protective structure also includes a first explosion-proof plate (27), which is disposed at the junction of the capacitor assembly (1) and the power module (2). The first explosion-proof plate (27) and the explosion-proof shell (4) located on the side of the power module (2) combine to form a protective space.

9. The protective structure for an MMC submodule according to claim 7, characterized in that, The protective structure also includes a second explosion-proof plate (28), which is located between the top surface of the stacked busbar assembly and the explosion-proof housing (4), and is fixed to the power module (2) and / or the capacitor assembly (1).

10. The protective structure for an MMC submodule according to claim 1, characterized in that, The power module (2) includes a support frame, a power device (21), a radiator (22) and a water pipe. The power device (21) and the radiator (22) are press-fitted and fixed on the support frame. The radiator (22) is sleeved and fixed on the outside of the power device (21). The water pipe is connected to the water passage inside the radiator (22). The protective structure also includes a blocking member fixed to the radiator (22), which is adapted to block the water pipe located in the peripheral space of the power device (21).

11. The protective structure for an MMC submodule according to claim 10, characterized in that, The water inlet pipe includes an outer water inlet pipe exposed to the outside, and the blocking member is fixed to the outside of the radiator (22) with an explosion-proof block (24) to shield the outer water inlet pipe.

12. The protective structure for an MMC submodule according to claim 11, characterized in that, The water inlet pipe also includes an inner water inlet pipe located inside, and the blocking member is a strip (25) embedded and fixed in the interval space of the radiator (22) to block the inner water inlet pipe.

13. The protective structure for an MMC submodule according to claim 10, characterized in that, The protective structure also includes an anti-pressure block (26), which is arranged along the pressing direction of the radiator (22).

14. The protective structure for an MMC submodule according to claim 13, characterized in that, The anti-pressure block (26) is made of insulating material and the surface of the anti-pressure block (26) is provided with anti-creep grooves (261), which are arranged opposite to the space between the anti-creep grooves (261) and the heat sink (22).

15. An MMC submodule, characterized in that, The protective structure of the MMC submodule as described in any one of claims 1 to 14 is adopted.

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