A high-voltage dry-type DC supported capacitor for rail transit

Abstract

This utility model discloses a high-voltage dry-type DC support capacitor for rail transit. The high-voltage dry-type DC support capacitor for rail transit includes a shell, a core module, a terminal assembly, and filling resin. The shell includes a housing, a shell bottom, a shell cover, and a mounting plate. The mounting plate includes a mounting plate body and a mounting nut. The core module includes a first core, a second core, inter-core insulation, core outer insulation, and bottom insulation. The first core includes a first element group, a first lead copper foil, a second lead copper foil, a first bus copper bus, a second bus copper bus, a first inter-group insulation, a second inter-group insulation, a third inter-group insulation, and a first insulating protective component. The second core includes a second element group, a third lead copper foil, a fourth lead copper foil, a third bus copper bus, a fourth bus copper bus, a fourth inter-group insulation, a fifth inter-group insulation, a sixth inter-group insulation, and a second insulating protective component. The terminal assembly includes an insulator, a conductive rod, a first insulating plate, a first electrode copper bus, a second insulating plate, a second electrode copper bus, a third insulating plate, a third electrode copper bus, and a fixing nut. This utility model has a simple structure and is easy to install and use. It can meet the requirements of long-term safe, stable and reliable operation of DC support capacitors for rail transit.

Description

Technical Field

[0001] This utility model belongs to the field of capacitor technology, specifically relating to a high-voltage dry-type DC support capacitor for rail transit. Background Technology

[0002] DC support capacitors are key components of converters, primarily serving functions such as voltage stabilization and filtering. Currently, dry-type DC support capacitors are widely used in the new rail transit sector. These capacitors are characterized by their dry-type structure, high voltage rating, and large capacitance.

[0003] With the development of power electronics technology, converters used in rail transit will adopt three-level and multi-level structures. In this structure, each DC capacitor has an internal series connection, allowing for higher rated voltage and larger capacitance, significantly reducing the size of the converter. Therefore, dry-type DC support capacitors with an internal series structure require the following characteristics: two independent capacitor units connected in series during use; high voltage and sufficient insulation strength; high current capacity; and low inductance.

[0004] Document CN107275087B discloses a DC capacitor for an ultra-high power three-level frequency converter. The capacitor consists of a shell, a core, terminals, resin filling, and a pressure relief valve. The core includes components, connecting copper foil, intermediate insulation, a fixed insulation plate, insulation protection components, a bottom insulation component, electrical lead-out copper foil, corner protection components, wrapping tape, and cover insulation. The terminals are mounted on the capacitor shell cover and connected to the electrical lead-out copper foil of the core, consisting of insulators, round nuts, guide rods, and sealing rings. This type of capacitor contains multiple independent capacitor units, which are externally connected in series during use to achieve series connection of the internal capacitors. However, the direct connection of the electrical lead-out copper foil of the core to the terminals results in a relatively large inductance in the capacitor.

[0005] Document CN209487322U discloses a power electronic capacitor for a flexible DC system, including a casing, a first core, and a second core. The first core includes a first component group, a first integral copper busbar, and a second integral copper busbar. The second core includes a second component group, a third integral copper busbar, and a fourth integral copper busbar. The integral copper busbar uses a low-inductance structure with soldered leads and is soldered to both ends of the component group. Although this type of capacitor uses an integral copper busbar soldering method to reduce inherent inductance, it only reduces the inductance between components. Since the first (third) and second (fourth) integral copper busbars are directly connected to the terminals, the connection inductance of this part cannot be reduced.

[0006] CN118645361A discloses a dry-type DC support capacitor for smart grids. This capacitor includes a shell, a core module, electrical connection components, terminal blocks, filled resin, a pressure relief valve, and a pressure switch. The core module includes a core shell, a component, component lead-out copper foil, and encapsulating resin. The electrical connection components include a busbar and electrical lead-out wires. The terminal blocks include an insulator, a conductive rod, a round nut, an insulating washer, a sealing ring, a first insulating plate, a first electrode copper busbar, a second insulating plate, and a second electrode copper busbar. While the connection method of the first and second electrode copper busbars reduces the capacitor's connection inductance, the inductance generated by the connection between the component lead-out copper foil and the first and second electrode copper busbars cannot be reduced.

[0007] Although the capacitors described above also have a multi-core capacitor structure and can solve the problems of heat dissipation, insulation, high current withstand, and low inductance, they also have their own disadvantages.

[0008] In summary, the key considerations for dry-type DC-supported capacitors with internal series structures are: low inductance structure; internal insulation structure; and heat dissipation structure. Solving these key technologies is the crucial point that needs to be addressed in the research and development of this type of capacitor. Summary of the Invention

[0009] To address the aforementioned key technical issues, this utility model proposes a high-voltage dry-type DC support capacitor for rail transit (hereinafter referred to as "capacitor").

[0010] The technical solution adopted in this utility model is as follows.

[0011] The capacitor includes a housing, core modules, terminal blocks, and filling resin. The housing includes a shell, a bottom, a cover, and a mounting bracket. The mounting bracket includes a mounting bracket body and a mounting nut. The core module includes a first core, a second core, inter-core insulation, core outer insulation, and bottom insulation. The first core includes a first element group, a first lead copper foil, a second lead copper foil, a first busbar, a second busbar, first inter-core insulation, second inter-core insulation, third inter-core insulation, and a first insulating protective element. The second core includes a second element group, a third lead copper foil, a fourth lead copper foil, a third busbar, a fourth busbar, fourth inter-core insulation, fifth inter-core insulation, sixth inter-core insulation, and a second insulating protective element. The terminal block assembly includes an insulator, a conductive rod, a first insulating plate, a first electrode copper busbar, a second insulating plate, a second electrode copper busbar, a third insulating plate, a third electrode copper busbar, and a fixing nut.

[0012] The first and second outgoing copper foils are respectively welded to the two ends of the first component group. The first busbar is installed between the first and second inter-group insulations. The second busbar is installed between the second and third inter-group insulations. The first outgoing copper foil is welded to the first busbar, and the second outgoing copper foil is welded to the second busbar. The first insulating protective component is installed on both sides of the first component group.

[0013] The third and fourth outgoing copper foils are respectively welded to the two ends of the second component group. The third busbar is installed between the fourth and fifth inter-group insulations. The fourth busbar is installed between the fifth and sixth inter-group insulations. The third outgoing copper foil is welded to the fourth busbar, and the fourth outgoing copper foil is welded to the third busbar. The second insulation protection components are installed on both sides of the second component group.

[0014] The insulator is placed inside the hole of the shell cover and sealed with sealant. The upper end of the conductive rod is placed inside the hole at the upper end of the insulator. The lower end of the conductive rod passes through the inner holes of the first insulating plate, the first electrode copper busbar, the second insulating plate, the second electrode copper busbar, the third insulating plate, and the third electrode copper busbar in sequence and is then tightened with a fixing nut.

[0015] The first busbar is welded to the first electrode busbar, and the second busbar is welded to the second electrode busbar.

[0016] The third busbar is welded to the second electrode busbar, and the fourth busbar is welded to the third electrode busbar. Inter-core insulation is installed between the first and second cores. The first and second cores are externally insulated, and the housing is topped with bottom insulation. The filling resin includes resin filling the gaps between core modules and between the core modules and the housing.

[0017] The outer shell, bottom, cover, and mounting brackets are all made of SU304 stainless steel with a thickness of 3mm.

[0018] The first component group consists of multiple components. The components are cylindrical in shape, with a metallized thin film wound around the core rod and gold-plated at both ends. They have the ability to self-heal after local breakdown.

[0019] The second component group consists of multiple components. The components are cylindrical in shape, with a metallized thin film wound around the core rod and gold-plated at both ends. They have the ability to self-heal after local breakdown.

[0020] Both the first and second component groups consist of multiple components. The components are cylindrical in shape, with a metallized thin film wound around a core rod and gold plating at both ends. They have the ability to self-heal after local breakdown.

[0021] The first outgoing copper foil is made of brass and is 0.5mm thick; the second outgoing copper foil is made of brass and is 0.5mm thick. The third lead-out copper foil is made of brass with a thickness of 0.5mm; the fourth lead-out copper foil is made of brass with a thickness of 0.5mm.

[0022] The first busbar is made of brass with a thickness of 1mm and a tin-plated surface; the second busbar is made of brass with a thickness of 1mm and a tin-plated surface; the third busbar is made of brass with a thickness of 1mm and a tin-plated surface; the fourth busbar is made of brass with a thickness of 1mm and a tin-plated surface.

[0023] The insulator is made of SMC composite material, with a groove on the top, a convex groove on the bottom, and an inner hole in the middle.

[0024] The conductive rod is made of brass, with a cylindrical upper end and an internal thread structure, a stepped cylinder in the middle, a smooth lower end, a square bottom, and a tin-plated outer surface.

[0025] The fixing nut is made of brass, with an internal hole in the middle and internal threads, and the outer surface is plated with nickel.

[0026] The first insulating board is made of 2 mm thick epoxy board with 3 square holes, each 17 mm long.

[0027] The first electrode busbar is made of brass with a thickness of 1 mm and a tin-plated surface. It has one square hole with a length of 17 mm and one round hole with a diameter of 30 mm.

[0028] The second insulation board is made of 2 mm thick epoxy board with 3 square holes, each 17 mm long.

[0029] The second electrode copper busbar is made of brass with a thickness of 1 mm and a tin-plated surface. It has one square hole with a length of 17 mm and two round holes with a diameter of 30 mm.

[0030] The third insulation board is made of 2 mm thick epoxy board with 3 square holes, each 17 mm long.

[0031] The third electrode busbar is made of brass with a thickness of 1 mm and a tin-plated surface. It has one square hole with a length of 17 mm and one round hole with a diameter of 30 mm.

[0032] The filling resin is polyurethane, with components A and B mixed in a ratio of 20:100, and a density of 0.92 g / cm³. 3 Flame retardant rating: V0.

[0033] Furthermore, the first electrode copper busbar has one folded edge, the second electrode copper busbar has two folded edges, the third electrode copper busbar has one folded edge, the first busbar is welded to the first electrode copper busbar at the folded edge, the second busbar and the third busbar are welded to the second electrode copper busbar at the two folded edges in sequence, and the fourth busbar is welded to the first electrode copper busbar at the folded edge.

[0034] The beneficial effects of this utility model are: the capacitor has the characteristics of internal series structure, low inductance, good heat dissipation performance, and good insulation performance, which solves the insulation and inductance problems of the internal series structure of the capacitor and improves the reliability of the capacitor.

[0035] This utility model has a simple structure and is easy to install and use. It can meet the requirements of long-term safe, stable and reliable operation of DC support capacitors for rail transit. Attached Figure Description

[0036] Figure 1 This is a schematic diagram illustrating an embodiment of the present utility model; Figure 2 for Figure 1 Top view; Figure 3 for Figure 1 The left view; Figure 4 for Figure 1 A schematic diagram of the frontal longitudinal section structure; Figure 5 for Figure 1 A schematic diagram of the longitudinal section structure viewed from behind; Figure 6 This is a schematic diagram of some components of the terminal block assembly; Figure 7 This is a schematic diagram of some components of the terminal block assembly; In the diagram, 1-outer shell; 2-core module; 3-filling resin; 4-terminal assembly; 11-Shell; 12-Shell bottom; 13-Shell cover; 14-Mounting climber; 21-First core; 22-Second core; 23-Inter-core insulation; 24-Core outer insulation; 25-Bottom insulation; 41-Insulator; 42-Conductive rod; 43-First insulating plate; 44-First electrode copper busbar; 45-Second insulating plate; 46-Second electrode copper busbar; 47-Third insulating plate; 48-Third electrode copper busbar; 49-Fixing nut; 141 - Install the climbing body; 142 - Install the nuts; 211-First component group; 212-First outgoing copper foil; 213-Second outgoing copper foil; 214-First busbar; 215-Second busbar; 216-First inter-group insulation; 217-Second inter-group insulation; 218-Third inter-group insulation; 219-First insulation protection element; 221 - Second component group; 222 - Third outgoing copper foil; 223 - Fourth outgoing copper foil; 224 - Third bus copper bus; 225 - Fourth bus copper bus; 226 - Fourth group inter-insulation; 227 - Fifth group inter-insulation; 228 - Sixth group inter-insulation; 229 - Second insulation protection component. Detailed Implementation

[0037] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0038] from Figures 1-7 visible: The capacitor includes a housing (1), a core module (2), filled resin (3), and a terminal assembly (4). The housing (1) includes a shell (11), a shell bottom (12), a shell cover (13), and a mounting plate (14). The mounting plate (14) includes a mounting plate body (141) and a mounting nut (142). The core module (2) includes a first core (21), a second core (22), core group insulation (23), core outer insulation (24), and bottom insulation (25). The first core (21) includes a first element group (211), a first lead copper foil (212), a second lead copper foil (213), a first busbar (214), a second busbar (215), a first inter-group insulation (216), and a second inter-group insulation (217). The second core (22) includes a second element group (221), a third outgoing copper foil (222), a fourth outgoing copper foil (223), a third busbar (224), a fourth busbar (225), a fourth inter-group insulation (226), a fifth inter-group insulation (227), a sixth inter-group insulation (228), and a second insulation protection element (229). The terminal assembly (4) includes an insulator (41), a conductive rod (42), a first insulating plate (43), a first electrode copper busbar (44), a second insulating plate (45), a second electrode copper busbar (46), a third insulating plate (47), a third electrode copper busbar (48), and a fixing nut (49). The first outgoing copper foil (212) and the second outgoing copper foil (213) are respectively welded to the two ends of the first component group (211). The first busbar (214) is installed between the first inter-group insulation (216) and the second inter-group insulation (217). The second busbar (215) is installed between the second inter-group insulation (217) and the third inter-group insulation (218). The first outgoing copper foil (212) is welded to the first busbar (214). The second outgoing copper foil (213) is welded to the second busbar (215). The first insulating protective element (219) is installed on both sides of the first component group (211). The third outgoing copper foil (222) and the fourth outgoing copper foil (223) are respectively welded to the two ends of the second component group (221). The third bus copper bus (224) is installed between the fourth inter-group insulation (226) and the fifth inter-group insulation (227). The fourth bus copper bus (225) is installed between the fifth inter-group insulation (227) and the sixth inter-group insulation (228). The third outgoing copper foil (222) is welded together with the fourth bus copper bus (225). The fourth outgoing copper foil (223) is welded together with the third bus copper bus (224). The second insulating protective element (229) is installed on both sides of the second component group (221). The insulator (41) is placed in the hole of the shell cover (13) and sealed with sealant. The upper end of the conductive rod (42) is placed in the hole at the upper end of the insulator (41). The lower end of the conductive rod (42) passes through the inner holes of the first insulating plate (43), the first electrode copper busbar (44), the second insulating plate (45), the second electrode copper busbar (46), the third insulating plate (47), and the third electrode copper busbar (48) in sequence and is then fastened with a fixing nut (49). The first busbar (214) is welded to the first electrode busbar (44), the second busbar (215) is welded to the second electrode busbar (46), the third busbar (224) is welded to the second electrode busbar (46), and the fourth busbar (225) is welded to the third electrode busbar (48). The core group insulation (23) is installed between the first core (21) and the second core (22). The first core (21) and the second core (22) are equipped with core outer insulation (24). The shell (11) is equipped with bottom insulation (25). The filling resin (3) includes the resin filling the gap between the core modules (2) and the gap between the core module (2) and the shell (1).

[0039] The shell (11), shell bottom (12), shell cover (13) and mounting plate (14) of the outer shell (1) are made of SU304 stainless steel, and the thickness is 3mm.

[0040] The first component group (211) consists of multiple components. The components are cylindrical in shape, with a metallized thin film wound on the core rod and gold sprayed at both ends. They have the ability to self-heal after local breakdown.

[0041] The second component group (221) consists of multiple components. The components are cylindrical in shape, with a metallized thin film wound on the core rod and gold sprayed at both ends. They have the ability to self-heal after local breakdown.

[0042] Both the first element group (211) and the second element group (221) consist of multiple elements. The elements are cylindrical in shape, with a metallized thin film wound around the core rod and gold sprayed at both ends. They have the ability to self-heal after local breakdown.

[0043] The first lead-out copper foil (212) is made of brass and has a thickness of 0.5 mm; the second lead-out copper foil (213) is made of brass and has a thickness of 0.5 mm; the third lead-out copper foil (222) is made of brass and has a thickness of 0.5 mm; and the fourth lead-out copper foil (223) is made of brass and has a thickness of 0.5 mm.

[0044] The first busbar (214) is made of brass with a thickness of 1 mm and is tin-plated on the surface; the second busbar (215) is made of brass with a thickness of 1 mm and is tin-plated on the surface; the third busbar (224) is made of brass with a thickness of 1 mm and is tin-plated on the surface; the fourth busbar (225) is made of brass with a thickness of 1 mm and is tin-plated on the surface.

[0045] The insulator (41) is made of SMC composite material, with a groove on the top, a convex groove on the bottom, and an inner hole in the middle.

[0046] The conductive rod (42) is made of brass, with a cylindrical upper end and an internal thread structure, a stepped cylinder in the middle, a smooth lower end, a square bottom, and a tin-plated outer surface.

[0047] The fixing nut (49) is made of brass, with an internal thread in the middle and nickel plated on the outer surface.

[0048] The first insulating board is made of 2 mm thick epoxy board with 3 square holes, each 17 mm long.

[0049] The first electrode copper busbar (44) is made of brass with a thickness of 1 mm and a tin-plated surface. It has a square hole with a length of 17 mm and a round hole with a diameter of 30 mm.

[0050] The second insulating board (45) is made of 2 mm thick epoxy board with 3 square holes with a length of 17 mm.

[0051] The second electrode copper busbar (46) is made of brass with a thickness of 1 mm and a tin-plated surface. It has one square hole with a length of 17 mm and two round holes with a diameter of 30 mm.

[0052] The third insulating board (47) is made of 2 mm thick epoxy board with 3 square holes with a length of 17 mm.

[0053] The third electrode copper busbar (48) is made of brass with a thickness of 1 mm and a tin-plated surface. It has a square hole with a length of 17 mm and a round hole with a diameter of 30 mm.

[0054] The filling resin (3) is polyurethane, with a mixing ratio of A and B components of 40:100 and a density of 0.92 g / cm³. 3 Flame retardant rating: V0.

[0055] Furthermore, the first electrode copper busbar (44) has one folded edge, the second electrode copper busbar (46) has two folded edges, the third electrode copper busbar (48) has one folded edge, the first busbar (214) is welded to the first electrode copper busbar (44) at the folded edge, the second busbar (215) and the third busbar (224) are welded to the second electrode copper busbar (46) at the two folded edges in sequence, and the fourth busbar (225) is welded to the first electrode copper busbar (44) at the folded edge.

[0056] The above description is merely a preferred embodiment of this utility model, but the protection scope of this utility model is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this utility model should be included within the protection scope of this utility model. Therefore, the protection scope of this utility model should be determined by the scope of the claims.

Claims

1. A high-voltage dry-type DC support capacitor for rail transit, characterized by: The high-voltage dry-type DC support capacitor for rail transit includes a shell, a core module, a terminal assembly, and filling resin. The shell includes a housing, a shell bottom, a shell cover, and a mounting plate. The mounting plate includes a mounting plate body and a mounting nut. The core module includes a first core, a second core, inter-core insulation, core outer insulation, and bottom insulation. The first core includes a first element group, a first lead copper foil, a second lead copper foil, a first busbar, a second busbar, first inter-core insulation, second inter-core insulation, third inter-core insulation, and a first insulating protective component. The second core includes a second element group, a third lead copper foil, a fourth lead copper foil, a third busbar, a fourth busbar, fourth inter-core insulation, fifth inter-core insulation, sixth inter-core insulation, and a second insulating protective component. The terminal assembly includes an insulator, a conductive rod, a first insulating plate, a first electrode copper busbar, a second insulating plate, a second electrode copper busbar, a third insulating plate, a third electrode copper busbar, and a fixing nut. The first and second outgoing copper foils are respectively welded to the two ends of the first component group. The first busbar is installed between the first inter-group insulation and the second inter-group insulation. The second busbar is installed between the second inter-group insulation and the third inter-group insulation. The first outgoing copper foil is welded to the first busbar. The second outgoing copper foil is welded to the second busbar. The first insulating protective component is installed on both sides of the first component group. The third and fourth outgoing copper foils are respectively welded to the two ends of the second component group. The third busbar is installed between the fourth and fifth inter-group insulations. The fourth busbar is installed between the fifth and sixth inter-group insulations. The third outgoing copper foil is welded to the fourth busbar. The fourth outgoing copper foil is welded to the third busbar. The second insulating protective components are installed on both sides of the second component group. The insulator is placed inside the hole of the shell cover and sealed with sealant. The upper end of the conductive rod is placed inside the hole at the upper end of the insulator. The lower end of the conductive rod passes through the inner holes of the first insulating plate, the first electrode copper busbar, the second insulating plate, the second electrode copper busbar, the third insulating plate, and the third electrode copper busbar in sequence and is then fastened with a fixing nut. The first busbar is welded to the first electrode busbar, the second busbar is welded to the second electrode busbar, the third busbar is welded to the second electrode busbar, and the fourth busbar is welded to the third electrode busbar. The core group insulation is installed between the first core and the second core. The first core and the second core are covered with core outer insulation. The shell is covered with bottom insulation. The filling resin includes resin filling the gaps between core modules and the gaps between the core modules and the shell.

2. The high voltage dry-type DC link capacitor for rail transportation of claim 1, wherein: The first electrode copper busbar is made of brass with a thickness of 1mm and a tin-plated surface. The first electrode copper busbar has a square hole with a length of 17mm, a round hole with a diameter of 30mm, and a folded edge.

3. The high voltage dry-type DC support capacitor for rail transit according to claim 1, characterized in that: The second electrode copper busbar is made of brass with a thickness of 1mm and a tin-plated surface. The second electrode copper busbar has one square hole with a length of 17mm, two round holes with a diameter of 30mm, and one folded edge.

4. The high voltage dry-type DC support capacitor for rail transit according to claim 1, characterized in that: The third electrode copper busbar is made of brass with a thickness of 1mm and a tin-plated surface. The third electrode copper busbar has a square hole with a length of 17mm, a round hole with a diameter of 30mm, and a folded edge.

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