High-current high-capacity direct-current support capacitor

Abstract

The utility model discloses a large-current large-capacity direct current support capacitor, which comprises a shell, a capacitor core module and a leading-out terminal, the capacitor core module comprises an absorption capacitor core group and a thin film capacitor core group, the absorption capacitor core group and the thin film capacitor core group are respectively provided with a plurality of capacitor core single groups which are respectively arranged in an array, and the leading-out terminal is connected with the absorption capacitor core group and the thin film capacitor core group. The absorption capacitor core group is positioned above the thin-film capacitor core group; electrodes at the two ends of the capacitor core module are respectively welded in parallel through a plurality of sub-copper plates, the upper ends of the sub-copper plates are connected with the laminated busbar, the leading-out terminal is arranged on the laminated busbar and extends out of the top of the shell, and the capacitor core module, the sub-copper plates and the laminated busbar are packaged in the shell through a potting material. According to the structure that the wire inlet end of the large-current large-capacity direct-current support capacitor is connected with the absorption capacitor in parallel to share high-frequency harmonic current, current impact can be borne under the condition that current distribution is not uniform, and heating breakdown failure is avoided.

Description

Technical Field

[0001] This utility model relates to the field of capacitor technology, and in particular to a high-current, high-capacity DC-Link capacitor. Background Technology

[0002] Capacitors (i.e., DC support capacitors) are one of the core components in converters, playing a role in stabilizing the DC bus voltage and absorbing AC components in the two-stage converter. They are widely used in frequency converters, rail transit, flexible DC transmission, new energy power generation, energy storage, and SVG (Static Var Generator).

[0003] Ripple current is one of the key parameters of DC-link capacitors and is the source of capacitor heating. If the temperature rise of the capacitor is too high during operation, it will accelerate the aging of the film, shorten the capacitor life, and may even lead to thermal breakdown.

[0004] During operation, the ripple current on the DC-Link capacitor is mainly the superposition of AC components from the rectifier and inverter terminals. If the ripple contains harmonic components of the same frequency as the inherent resonant frequency, the system will experience series resonance, and this loop will become a low-impedance loop. Since the equivalent series resistance (ESR) of the DC-Link capacitor and the equivalent resistance (RDC) on the DC bus are both in the mΩ range, even a small ripple component on the bus will generate a large ripple current. After resonance occurs, the huge loop current will produce a large voltage drop across the capacitor, causing abnormal heating. If this exceeds the capacitor's withstand voltage, the capacitor will break down and fail.

[0005] In general, a large margin is left when selecting and designing capacitors to avoid excessive temperature rise. However, this increases the cost and size of the product, which is contrary to the current trend of small size, high current, high energy density and high power.

[0006] Chinese Patent Document No. CN219303486U, published on July 4, 2023, discloses a low-loss, low-temperature-rise DC-DC supported capacitor, comprising a shell, insulating filler, capacitor core, copper busbar assembly, and lead-out copper busbar unit. The capacitor core includes multiple capacitor elements. Each copper busbar assembly sequentially includes a bottom copper busbar, a middle copper busbar, and a top copper busbar disposed on one side of the capacitor core. The bottom copper busbar includes a bottom copper busbar body, a first bending plate, and a first mounting hole. The middle copper busbar includes a middle copper busbar body, a second bending plate, and a second mounting hole. The top copper busbar includes a top copper busbar body, a third bending plate, and a third mounting hole. The bottom copper busbar body, the middle copper busbar body, and the top copper busbar body have the same length, and their widths decrease sequentially. The copper busbars (leads) at the input and output terminals of this structure are arranged horizontally, resulting in poor current carrying capacity and overheating. Since all capacitor cores are identical, harmonics are not specifically absorbed when the above situation occurs, leading to series resonance. In addition, the misaligned arrangement of capacitor cores and the overly compact structure affect heat dissipation. Therefore, the capacitor will generate abnormal heat, eventually exceeding its withstand voltage value and causing it to break down and fail. Utility Model Content

[0007] The purpose of this invention is to provide a high-current, high-capacity DC support capacitor with a reasonable structure, capable of sharing high-frequency harmonic current, and with a long lifespan.

[0008] The purpose of this utility model is achieved as follows:

[0009] A high-current, high-capacity DC-DC supported capacitor includes a housing, a capacitor core module, and lead terminals. The capacitor core module includes an absorption capacitor core group and a film capacitor core group. The absorption capacitor core group and the film capacitor core group each have multiple individual capacitor cores arranged in an array. The absorption capacitor core group is located above the film capacitor core group. The two electrodes of the capacitor core module are respectively welded in parallel through multiple sub-copper plates. The upper end of the sub-copper plates is connected to a multilayer busbar. The lead terminals are disposed on the multilayer busbar and extend out of the top of the housing. The capacitor core module, sub-copper plates, and multilayer busbar are encapsulated in the housing using potting compound.

[0010] The objective of this utility model can also be achieved by the following technical measures:

[0011] As a more specific embodiment, the stacked busbar includes an outer busbar copper plate, an insulating layer, and an inner busbar copper plate stacked sequentially; the sub-copper plates include an input pole sub-copper plate and an output pole sub-copper plate, the upper ends of which are electrically connected to the outer busbar copper plate and the inner busbar copper plate, respectively, or the upper ends of which are electrically connected to the inner busbar copper plate and the outer busbar copper plate, respectively.

[0012] As a further embodiment, an insulator is provided on the outer periphery of the lead-out terminal.

[0013] As a further embodiment, the lead-out terminals include input lead-out terminals and output lead-out terminals. The lower end of the input lead-out terminal is electrically connected to the outer busbar copper plate. The outer busbar copper plate and the insulating layer have openings corresponding to the output lead-out terminals. The output lead-out terminals pass through the openings and are electrically connected to the inner busbar copper plate. Alternatively, the outer busbar copper plate and the insulating layer have openings corresponding to the output lead-out terminals. The input lead-out terminals pass through the openings and are electrically connected to the inner busbar copper plate. The lower end of the output lead-out terminals is electrically connected to the outer busbar copper plate.

[0014] As a further embodiment, the input pole copper plate and the output pole copper plate are arranged in a comb-like pattern, and the input pole copper plate and the output pole copper plate are electrically connected to the corresponding busbar copper plate or integrally formed.

[0015] As a further option, the input pole copper plate and the output pole copper plate are arranged symmetrically.

[0016] As a further embodiment, each individual unit of the capacitor core module includes one capacitor core, or each individual unit includes two or more capacitor cores connected in series.

[0017] As a further embodiment, the diameter of the absorbing capacitor core is smaller than the diameter of the film capacitor core, the number of absorbing capacitor cores arranged laterally is greater than the number of film capacitor cores arranged laterally, and the number of absorbing capacitor cores arranged vertically is less than the number of film capacitor cores arranged vertically.

[0018] As a further embodiment, the capacitor core module, the sub-copper plate, and the stacked busbar are separated from the inner wall of the outer casing, and the outer casing is a metal casing or a plastic casing; the input lead-out terminal and the output lead-out terminal are each provided in twos and are arranged alternately.

[0019] The beneficial effects of this utility model are as follows:

[0020] (1) The structure of the parallel absorption capacitor at the input end of this high current and high capacity DC support capacitor to share the high frequency harmonic current can ensure that it can withstand the current impact without overheating and breakdown failure under uneven current distribution.

[0021] (2) The input and output copper plates of this high-current and high-capacity DC support capacitor are symmetrically arranged, and multiple capacitor cores are connected in a single symmetrical manner, which can achieve better current sharing; the design of the stacked busbar copper plate can also greatly improve the overall overcurrent capacity of the capacitor, effectively reduce the temperature rise of the capacitor, achieve small volume and large current, and meet the requirements of high current operating conditions. Attached Figure Description

[0022] Figure 1 This is an exploded structural diagram of an embodiment of the present invention.

[0023] Figure 2 This is a schematic diagram of the main structure of the present invention in a perspective view after assembly.

[0024] Figure 3 This is a side view of the assembled structure of this utility model.

[0025] Figure 4 for Figure 2 A schematic diagram of the AA cross-sectional structure.

[0026] Figure 5 for Figure 4 Enlarged structural diagram of point F (one lead-out terminal).

[0027] Figure 6 This is a schematic diagram of another lead-out terminal structure in this utility model. Detailed Implementation

[0028] The present invention will be further described below with reference to the accompanying drawings and embodiments:

[0029] See Figures 1-6 As shown, a high-current, high-capacity DC-DC supported capacitor includes a housing 10, a capacitor core module 20, and lead terminals 3. The capacitor core module 20 includes an absorption capacitor core group 201 and a film capacitor core group 202. The absorption capacitor core group 201 and the film capacitor core group 202 are respectively provided with multiple capacitor core groups and arranged in an array. The absorption capacitor core group 201 is located above the film capacitor core group 202. The two end electrodes of the capacitor core module 20 are respectively welded in parallel through multiple sub-copper plates 40. The upper end of the sub-copper plates 40 is connected to a multilayer busbar 30. The lead terminals 3 are disposed on the multilayer busbar 30 and extend out of the top of the housing 10. The capacitor core module 20, the sub-copper plates 40, and the multilayer busbar 30 are encapsulated in the housing 10 by potting compound 6.

[0030] The stacked busbar 30 includes an outer busbar copper plate 11, an insulating layer 8, and an inner busbar copper plate 22 stacked sequentially; the sub-copper plate 40 includes an input pole sub-copper plate and an output pole sub-copper plate, the upper ends of which are electrically connected to the outer busbar copper plate 11 and the inner busbar copper plate 22, respectively.

[0031] An insulator 31 is provided on the outer periphery of the lead-out terminal 3.

[0032] The lead-out terminal 3 includes an input lead-out terminal B and an output lead-out terminal C. The lower end of the input lead-out terminal B is electrically connected to the outer busbar copper plate 11. The outer busbar copper plate 11 and the insulating layer 8 are provided with openings corresponding to the output lead-out terminal C. The output lead-out terminal C passes through the openings and is electrically connected to the inner busbar copper plate 22.

[0033] The input and output copper plates are arranged in a comb-like pattern, and are electrically connected to or integrally formed with the corresponding busbar copper plates.

[0034] The input and output copper plates are arranged symmetrically.

[0035] Each unit of the capacitor core module 20 includes two capacitor cores connected in series. Specifically, the absorption capacitor core group 201 includes multiple absorption capacitor core groups D, each absorption capacitor core group D including two absorption capacitor cores 4 connected in series; the film capacitor core group 202 includes multiple film capacitor core groups E, each film capacitor core group E including two film capacitor cores 5 connected in series.

[0036] The diameter of the absorbing capacitor core 4 is smaller than the diameter of the film capacitor core 5. The number of absorbing capacitor cores 4 arranged laterally is greater than the number of film capacitor cores 5 arranged laterally, and the number of absorbing capacitor cores 4 arranged vertically is less than the number of film capacitor cores 5 arranged vertically.

[0037] The capacitor core module 20, the copper plate 40, and the stacked busbar 30 are separated from the inner wall of the outer shell 10. The outer shell 10 is a metal shell 10 or a plastic shell 10. The input lead-out terminal B and the output lead-out terminal C are provided in twos respectively and are arranged alternately.

[0038] The above describes the preferred embodiments of this utility model, illustrating and describing its basic principles, main features, and advantages. Those skilled in the art should understand that this utility model is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of this utility model. Various changes and modifications can be made without departing from the spirit and scope of this utility model, and all such changes and modifications fall within the scope of protection of this utility model as defined by the appended claims and their equivalents.

Claims

1. A high-current, high-capacity DC-supported capacitor, comprising a housing (10), a capacitor core module (20), and lead terminals (3), characterized in that: The capacitor core module (20) includes an absorption capacitor core group (201) and a thin film capacitor core group (202). The absorption capacitor core group (201) and the thin film capacitor core group (202) are respectively provided with multiple capacitor core groups and arranged in an array. The absorption capacitor core group (201) is located above the thin film capacitor core group (202). The two electrodes of the capacitor core module (20) are respectively welded in parallel through multiple sub-copper plates (40). The upper end of the sub-copper plate (40) is connected to the stacked busbar (30). The lead-out terminal (3) is set on the stacked busbar (30) and extends out of the top of the outer shell (10). The capacitor core module (20), the sub-copper plate (40) and the stacked busbar (30) are encapsulated in the outer shell (10) by potting material (6).

2. The high-current, high-capacity DC-supported capacitor according to claim 1, characterized in that: The stacked busbar (30) includes an outer busbar copper plate (11), an insulating layer (8), and an inner busbar copper plate (22) stacked sequentially. The sub-copper plate (40) includes an input pole sub-copper plate and an output pole sub-copper plate. The upper ends of the input pole sub-copper plate and the output pole sub-copper plate are electrically connected to the outer busbar copper plate (11) and the inner busbar copper plate (22), respectively. Alternatively, the upper ends of the input pole sub-copper plate and the output pole sub-copper plate are electrically connected to the inner busbar copper plate (22) and the outer busbar copper plate (11), respectively.

3. The high-current, high-capacity DC-supported capacitor according to claim 2, characterized in that: An insulator (31) is provided on the outer periphery of the lead-out terminal (3).

4. The high-current, high-capacity DC-supported capacitor according to claim 3, characterized in that: The lead-out terminal (3) includes an input lead-out terminal (B) and an output lead-out terminal (C). The lower end of the input lead-out terminal (B) is electrically connected to the outer busbar copper plate (11). The outer busbar copper plate (11) and the insulating layer (8) have openings corresponding to the output lead-out terminal (C). The output lead-out terminal (C) passes through the openings and is electrically connected to the inner busbar copper plate (22). Alternatively, the outer busbar copper plate (11) and the insulating layer (8) have openings corresponding to the output lead-out terminal (C). The input lead-out terminal (B) passes through the openings and is electrically connected to the inner busbar copper plate (22). The lower end of the output lead-out terminal (C) is electrically connected to the outer busbar copper plate (11).

5. The high-current, high-capacity DC-supported capacitor according to claim 2, characterized in that: The input and output copper plates are arranged in a comb-like pattern, and are electrically connected to or integrally formed with the corresponding busbar copper plates.

6. The high-current, high-capacity DC-supported capacitor according to claim 2, characterized in that: The input and output copper plates are arranged symmetrically.

7. The high-current, high-capacity DC-supported capacitor according to claim 1, characterized in that: Each unit of the capacitor core module (20) includes one capacitor core, or each unit includes two or more capacitor cores connected in series.

8. The high-current, high-capacity DC-supported capacitor according to claim 1, characterized in that: The diameter of the absorbing capacitor core (4) is smaller than the diameter of the film capacitor core (5). The number of absorbing capacitor cores (4) arranged laterally is greater than the number of film capacitor cores (5) arranged laterally, and the number of absorbing capacitor cores (4) arranged vertically is less than the number of film capacitor cores (5) arranged vertically.

9. The high-current, high-capacity DC-supported capacitor according to claim 4, characterized in that: The capacitor core module (20), the copper plate (40) and the stacked busbar (30) are separated from the inner wall of the outer shell (10). The outer shell (10) is a metal shell (10) or a plastic shell (10). The input lead-out terminal (B) and the output lead-out terminal (C) are provided in twos and are arranged alternately.

Images