CN220420450U

CN220420450U - DC supporting capacitor

Info

Publication number: CN220420450U
Application number: CN202321810602.4U
Authority: CN
Inventors: 彭绮梦
Original assignee: Gree Electric Appliances Inc of Zhuhai; Zhuhai Gree Xinyuan Electronics Co Ltd
Current assignee: Gree Electric Appliances Inc of Zhuhai; Zhuhai Gree Xinyuan Electronics Co Ltd
Priority date: 2023-07-10
Filing date: 2023-07-10
Publication date: 2024-01-30
Anticipated expiration: 2033-07-10

Abstract

The utility model provides a direct-current support capacitor, which comprises a shell, wherein a first capacitor core and a second capacitor core are axially arranged in the shell; the first capacitor core is connected with the second capacitor core in parallel, the first capacitor core is close to the capacitor leading-out end, and the second capacitor core is close to the bottom of the shell; the first capacitor core and the second capacitor core are formed by winding at least two layers of metallized films, and the film width of the first capacitor core is smaller than that of the second capacitor core. The direct-current support capacitor adopts a structure that cores with different film widths are connected in parallel up and down, the capacitor core with a shorter film width is arranged on the upper surface and is close to the capacitor leading-out end, and the capacitor core with a longer film width is arranged on the lower surface and is close to the bottom of the shell.

Description

DC supporting capacitor

Technical Field

The utility model relates to the technical field of capacitors, in particular to a direct-current supporting capacitor.

Background

The DC supporting capacitor, also called DC-Link capacitor, generally comprises a capacitor core and a shell, wherein the capacitor core is positioned in the shell, the capacitor core is formed by winding a metallized film (a plastic film is coated with a metal layer to serve as an electrode), the capacitor core formed by winding is generally flat (namely square) or cylindrical, a metal spraying layer is attached to the end face of the formed capacitor core to lead out the capacity, and then copper wires are welded at two ends of the capacitor core to serve as leading-out ends.

Currently, a dc supporting capacitor is used as one of key components of a current transformer, and plays roles of stabilizing voltage, filtering and the like in the current transformer. In the fields of photovoltaics, wind energy and the like, the requirements of the high-frequency photovoltaic inverter are increased, the peak conversion efficiency of the high-frequency photovoltaic inverter can reach more than 90%, so that the power density of a circuit is greatly improved, as the requirements of the converters in the new energy fields of high-frequency photovoltaics, wind energy and the like are larger and larger, the requirements of the corresponding high-frequency resistant DC-Link capacitor are gradually increased, and on the premise that the size is unchanged, the requirements of the corresponding high-frequency resistant DC-Link capacitor on heating and electrical property parameter stability are higher and higher.

At present, the research on self-healing and heating of an alternating-current metallized capacitor in the industry is quite plenty, and the research on a direct-current supporting capacitor is quite little, so that the current technical difficulty is how to greatly reduce the internal heating of the metallized film direct-current supporting capacitor through the optimized design under the condition that the structural size is unchanged, and meanwhile, the metallized film direct-current supporting capacitor has stable and good electrical performance parameters.

Disclosure of Invention

The utility model aims to provide a direct-current supporting capacitor, which solves the problem that the temperature rise of the capacitor of the existing DCL-ink capacitor is too high under high-frequency harmonic high current.

In order to achieve the above purpose, the technical scheme of the utility model is as follows:

a direct current support capacitor comprises a shell, wherein a first capacitor core and a second capacitor core are axially arranged in the shell;

the first capacitor core is connected with the second capacitor core in parallel, the first capacitor core is close to the capacitor leading-out end, and the second capacitor core is close to the bottom of the shell;

the first capacitor core and the second capacitor core are formed by winding at least two layers of metallized films, and the film width of the first capacitor core is smaller than that of the second capacitor core.

The direct current supporting capacitor of this application adopts parallel structure about the wide core of different membranes, and the wide shorter electric capacity core of membrane is above, is close to the electric capacity and draws forth the end, and the wide longer electric capacity core of membrane is below, is close to the casing bottom, and this design can effectively reduce the Equivalent Series Resistance (ESR) of condenser to reduce the product and generate heat, and then make the direct current supporting capacitor of this application have resistant heavy current, high frequency resistant, internal temperature rise low characteristics.

In some embodiments, the first capacitive core and the second capacitive core are coaxially disposed.

The DC supporting capacitor adopts a core centering positioning design, so that the stability of various electrical performance parameters of the capacitor can be further improved.

In some embodiments, a first copper connection strap and a second copper connection strap are disposed within the housing;

the first connecting copper strips and the second connecting copper strips are symmetrically distributed along the periphery of the capacitor core;

the first connecting copper strip is used for connecting two ends of the first capacitor core and the second capacitor core, which are away from each other, in parallel and then leading out the two ends;

the second connecting copper strip is used for connecting two ends, close to each other, of the first capacitor core and the second capacitor core in parallel and then leading out the two ends.

The direct current supporting capacitor of this application, the copper strips of connecting the core is located the core outside, and for the periphery symmetric distribution of core, compare in the inside line of walking of core, can improve the heat dispersion of product, further reduce inside temperature rise.

In some embodiments, the first connecting copper strap is two.

The direct current supporting capacitor of this application, the both ends that two cores deviate from each other are connected to first connecting copper strips, and length is longer, adopts two wiring designs, when guaranteeing to laminate with the core, increases the cross sectional area of copper strips, improves the overcurrent ability of copper strips, reduces the calorific capacity of copper strips, and then reduces the product and generate heat.

In some embodiments, the housing is a cylindrical housing with an open end, the open end of the housing is provided with an end cover, and the end cover is provided with a first lead-out terminal and a second lead-out terminal;

the first capacitor core is arranged close to the end cover;

the first connecting copper strip is connected with the first lead-out terminal, and a through hole is formed in the end part of the first connecting copper strip, which is connected with the first lead-out terminal;

the second connecting copper strip is connected with the second leading-out terminal, and a through hole is formed in the end portion, connected with the second leading-out terminal, of the second connecting copper strip.

The through hole is seted up to the junction of copper strips and leading-out terminal, in the soldering process of copper strips and leading-out terminal, because of the via hole design of copper strips welded part, it is better to cross tin ability, reducible welding resistance, and the reduction loss, and then the reduction product generates heat.

In some embodiments, a potting compound is disposed between the first and second capacitive cores and the housing.

The direct current supporting capacitor utilizes the pouring material to fix the core in the shell in a sealing way, and can play roles in protection, insulation and moisture prevention.

Preferably, the direct-current support capacitor adopts epoxy resin with good heat dissipation performance as the casting material, and has low cost and excellent performance.

In some embodiments, the first capacitive core is provided with a first insulating sleeve near one end of the end cap and the second capacitive core is provided with a second insulating sleeve near one end of the housing.

The DC supporting capacitor has the advantages that the insulating sleeve is arranged on the upper end face of the core, the problem of interelectrode short circuit between the metal spraying layer on the upper end face of the core and the leading-out terminal of the end cover can be avoided, the insulating sleeve is arranged on the lower end face of the core, and the problem of electrode shell short circuit between the metal spraying layer on the lower end face of the core and the bottom face of the shell can be avoided.

In some embodiments, the metallized film includes a base film and a metal plating layer disposed on the base film;

the width of the base film is larger than that of the metal plating layer, so that a clearance area is formed on one side of the metallized film, and the other side of the metallized film opposite to the clearance area is provided with a wavy trimming edge;

the wavy trimming edges on two adjacent layers of the metallized films are respectively positioned at two ends of the capacitor core to be contacted with the metal spraying layer.

The direct-current support capacitor has the advantages that the metallized film adopts the wave slitting mode, the contact area between the metal spraying layer and the end face of the capacitor core is increased, the adhesive force of the metal spraying layer is improved, the overcurrent capacity is increased, and the product loss angle is reduced.

In some embodiments, the metal coating is formed on the surface of the base film by vacuum evaporation, and the plating vacuum degree is less than or equal to 4.0E ^-4 mbar。

In some embodiments, the sheet resistance of the metal coating is 25 to 60 Ω/≡.

The direct-current support capacitor has the advantages that the metallized film adopts a low-vacuum self-plating technology, the sheet resistance of the active area is moderate, the charge and discharge resistance and the ripple current resistance can be improved, and the accumulated heat quantity in high ripple current is less.

According to the technical scheme, the direct-current support capacitor has the following beneficial effects:

1. the unique double-core structure design with different film widths reduces the equivalent series resistance of the product, and is resistant to high current and high frequency.

2. The core centering design is adopted, so that the stability of the electrical performance parameters is improved.

3. The widened copper strips are adopted, so that the equivalent series resistance of the product is reduced, the heating copper strips are connected along the outside of the core, the heat dissipation capacity of the product is improved, and the internal temperature rise is reduced.

Drawings

The accompanying drawings, which are included to provide a further understanding of the utility model and are incorporated in and constitute a part of this specification, illustrate embodiments of the utility model and together with the description serve to explain the utility model.

Fig. 1 is a front cross-sectional view of a dc support capacitor according to an embodiment of the present utility model;

FIG. 2 is an axial view of a DC support capacitor according to an embodiment of the present utility model;

FIG. 3 is a top view of a DC support capacitor according to an embodiment of the present utility model;

FIG. 4 is a schematic diagram of the connection between a capacitor core and a copper strip according to an embodiment of the present utility model;

FIG. 5 is an axial view of an end cap of an embodiment of the present utility model;

FIG. 6 is a cross-sectional view of a two-layer metallized film of an embodiment of the utility model when wound;

FIG. 7 is a top view of a two-layer metallized film in accordance with an embodiment of the present utility model when wound;

FIG. 8 is an isometric view of a two-layer metallized film of an embodiment of the utility model when wound;

wherein:

1-a housing; 2-a first capacitive core; 3-a second capacitive core; 4-a first connecting copper strip; 5-a second connecting copper strip; 6-end caps; 7-a first lead-out terminal; 8-a second lead-out terminal; 9, pouring materials; 10-a first insulating cover; 11-a second insulating cover;

a 100-base film; 110-metal plating; 120-leaving a dead zone; 130-wave trimming.

Detailed Description

Preferred embodiments of the present utility model will be described in more detail below with reference to the accompanying drawings. While the preferred embodiments of the present utility model are shown in the drawings, it should be understood that the present utility model may be embodied in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the utility model to those skilled in the art.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the utility model. As used in this specification and the appended claims, the singular forms "a," "an," and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It should also be understood that the term "and/or" as used herein refers to and encompasses any or all possible combinations of one or more of the associated listed items.

It should be understood that although the terms "first," "second," "third," etc. may be used herein to describe various information, these information should not be limited by these terms. These terms are only used to distinguish one type of information from another. For example, first information may also be referred to as second information, and similarly, second information may also be referred to as first information, without departing from the scope of the utility model. Thus, a feature defining "a first" or "a second" may explicitly or implicitly include one or more such feature. In addition, in the description of the present utility model, the meaning of "a plurality" is two or more, unless explicitly defined otherwise.

The direct current support capacitor is used as one of key components of the current transformer, and plays roles of stabilizing voltage, filtering and the like in the current transformer. In the fields of photovoltaics, wind energy and the like, the requirements of the high-frequency photovoltaic inverter are increased, the peak conversion efficiency of the high-frequency photovoltaic inverter can reach more than 90%, so that the power density of a circuit is greatly improved, as the requirements of the converters in the new energy fields of high-frequency photovoltaics, wind energy and the like are larger and larger, the requirements of the corresponding high-frequency resistant DC-Link capacitor are gradually increased, and on the premise that the size is unchanged, the requirements of the corresponding high-frequency resistant DC-Link capacitor on heating and electrical property parameter stability are higher and higher.

The direct current support capacitor generally comprises a capacitor core and a shell, wherein the capacitor core is positioned in the shell and is formed by winding a metallized film (a plastic film is coated with a metal layer to serve as an electrode), the capacitor core which is generally wound and formed is flat (namely square) or cylindrical, a metal spraying layer is attached to the end face of the formed capacitor core to be used for leading out capacity, and then copper wires are welded at two ends of the capacitor core to serve as leading-out ends.

Therefore, the utility model provides a direct-current supporting capacitor to solve the problem that the temperature rise of the capacitor of the existing DCL-ink capacitor is too high under high-frequency harmonic high current.

As shown in fig. 1 to 5, a dc supporting capacitor includes a housing 1, a first capacitor core 2 and a second capacitor core 3 are disposed in the housing 1 along an axial direction, where the first capacitor core 2 and the second capacitor core 3 are connected in parallel, the first capacitor core 2 is close to a capacitor lead-out end, the second capacitor core is close to a bottom of the housing 1, the first capacitor core 2 and the second capacitor core 3 are formed by winding at least two layers of metallized films, and a film width of the first capacitor core 2 is smaller than a film width of the second capacitor core 3.

By applying the technical scheme of the embodiment, the conventional capacitor cores are split into two, the first capacitor core 2 with a shorter film width is arranged on the upper surface and is close to the capacitor leading-out end, the second capacitor core 3 with a longer film width is arranged on the lower surface and is close to the bottom of the shell 1, and the unique different film width cores are connected in parallel up and down, so that the Equivalent Series Resistance (ESR) of the capacitor can be effectively reduced, the product heating is reduced under the condition of meeting the withstand voltage of the product, and the direct-current supporting capacitor has the characteristics of high current resistance, high frequency resistance and low internal temperature rise.

In this application, the film width of the first capacitor core 2 is smaller than the film width of the second capacitor core 3, which means that the width of the metallized film of the first capacitor core 2 is smaller than the width of the metallized film of the second capacitor core 3.

As shown in fig. 1, the first capacitor core 2 and the second capacitor core 3 are coaxially arranged in the shell 1, and the core is centrally positioned, so that the stability of various electrical performance parameters of the capacitor can be further improved.

As shown in fig. 1 to 5, which show a cylindrical dc support capacitor, a case 1 is a cylindrical case having one end provided open, and a first connection copper strip 4 and a second connection copper strip 5 are provided in the case 1.

Referring to fig. 1, the first and second connection copper strips 4 and 5 are located outside the first and second capacitance cores 2 and 3 and symmetrically distributed with respect to the centers of the first and second capacitance cores 2 and 3.

The first copper connecting strip 4 is used for connecting two ends of the first capacitor core 2 and the second capacitor core 3, which are away from each other, in parallel and then leading out the two ends, namely, the first copper connecting strip 4 is electrically connected with the metal spraying layer on the upper end face of the first capacitor core 2 and the metal spraying layer on the lower end face of the second capacitor core 3 at the same time.

Meanwhile, the second connecting copper strip 5 is used for leading out the two ends, close to each other, of the first capacitor core 2 and the second capacitor core 3 after being connected in parallel, namely, the second connecting copper strip 5 is electrically connected with the metal spraying layer on the lower end face of the first capacitor core 2 and the metal spraying layer on the upper end face of the second capacitor core 3 at the same time. In this way, a parallel connection of the first capacitive core 2 and the second capacitive core 3 is achieved.

Referring to fig. 1 and 4, in the dc support capacitor of the present application, the first connection copper strip 4 and the second connection copper strip 5 are located outside the first capacitor core 2 and the second capacitor core 3, and are symmetrically distributed with respect to the first capacitor core 2 and the second capacitor core, compared with the routing from the inside of the capacitor core, for example, the routing from the core rod of the capacitor core, the heat dissipation capability of the product can be obviously improved, and thus the internal temperature rise of the capacitor is further reduced.

Referring to fig. 1, since the first connection copper strip 4 connects the upper end surface of the first capacitor core 2 and the lower end surface of the second capacitor core 3, the length is relatively long, in order to reduce the heat productivity of the first connection copper strip 4, the first connection copper strip 4 is arranged to be two, thus, while ensuring that the first connection copper strip 4 is attached to the first capacitor core 2 and the second capacitor core 3, the cross-sectional area of the first connection copper strip 4 is increased, thereby improving the overcurrent capacity thereof, reducing the heat productivity, and further reducing the heat productivity of the product.

Alternatively, the first and second connection copper strips 4, 5 are each 0.4X115 mm tin-plated copper strips.

As shown in fig. 1 to 5, the open end of the housing 1 is provided with an end cap 6, the first capacitive core 2 is provided close to the end cap 6, and the end cap 6 is provided with a first lead-out terminal 7 and a second lead-out terminal 8.

The first connecting copper strip 4 is connected with the first leading-out terminal 7 so as to lead out the upper end of the first capacitor core 2 and the lower end of the second capacitor core 3 in parallel, and the second connecting copper strip 5 is connected with the second leading-out terminal 8 so as to lead out the lower end of the first capacitor core 2 and the upper end of the second capacitor core 3 in parallel.

Referring to fig. 4, the end of the first connection copper strip 4 connected to the first lead-out terminal 7, and the end of the second connection copper strip 5 connected to the second lead-out terminal 8 are all provided with through holes. Therefore, in the soldering process of the copper strip and the lead-out terminal, the tin passing capability is better due to the design of the through hole at the welding part of the copper strip, the welding resistance can be reduced, the loss is reduced, and then the heating of the product is reduced.

As shown in fig. 1, a casting material 9 is arranged between the first capacitor core 2 and the second capacitor core 3 and the shell 1, and the casting material is used for sealing and fixing the cores in the shell, so that the effects of protection, insulation and moisture prevention can be achieved. Preferably, the casting material 9 is epoxy resin with good heat dissipation performance, low cost and excellent performance.

Referring to fig. 1 and 4, a first insulating sleeve 10 is disposed at the upper end of the first capacitor core 2 near the end cover 6, and a second insulating sleeve 11 is disposed at the lower end of the second capacitor core 3 near the bottom of the housing 1.

In general, epoxy resin is filled between the metal spraying layer on the upper end surface of the first capacitor core 2 and the lead-out terminal of the end cover 6, so that an insulation effect can be achieved, but because the gap between the metal spraying layer on the upper end surface of the first capacitor core 2 and the lead-out terminal of the end cover 6 is relatively short, if the epoxy resin is not filled well, inter-electrode short circuit can occur, so that the situation can be completely avoided, and because the metal spraying layer on the upper end surface of the first lead-out terminal 7 and the first capacitor core 2 are communicated through the first connecting copper strip 4, the inter-electrode short circuit problem does not exist, the first insulating sleeve 10 is arranged into a fan shape, so that the second connecting copper strip 5 and the second lead-out terminal 8 are insulated from the metal spraying layer on the upper end surface of the first capacitor core 2, and materials are saved while insulation requirements are met.

Similarly, the epoxy resin is filled between the metal spraying layer on the lower end surface of the second capacitor core 3 and the bottom surface of the shell 1, so that an insulating effect can be achieved, but because the space between the metal spraying layer and the bottom surface of the shell is relatively close, if the epoxy resin is poorly filled, a short circuit of a polar shell is likely to occur, so that the electrification is ignited, and the arrangement of the second insulating sleeve 11 can completely avoid the occurrence of the situation, and the second insulating sleeve 11 is circular and entirely sleeves the bottom of the second capacitor core 3.

Optionally, the first insulating sleeve 10 and the second insulating sleeve 11 are made of PP material.

The first capacitor core 2 and the second capacitor core 3 have the same structure and are formed by winding at least two layers of metallized films, but the width of the metallized films used for the two layers is different, and referring to fig. 6 to 8, the metallized films include a base film 100 and a metal plating layer 110 disposed on the base film 100.

The width of the base film 100 is greater than that of the metal plating layer 110, so that a hollow area 120 is formed on one side of the metallized film, a wavy trimming 130 is formed on the other side of the metallized film opposite to the hollow area 120, the wavy trimming 130 on two adjacent layers of metallized films are respectively positioned at two ends of the capacitor core to be contacted with the metal spraying layer, and the hollow area 120 of the metallized film positioned at the inner layer is positioned at the inner side of the wavy trimming 130 of the metallized film at the outer layer in the winding process.

As the metallized film adopts the wave slitting mode, compared with the straight slitting flat edge of the metallized film in the prior art, the contact area between the metal spraying layer and the end surface of the capacitor core is increased during metal spraying, the adhesive force of the metal spraying material is improved, the overcurrent capacity of the capacitor core can be increased, and the product loss angle is reduced.

The base film 100 may be formed of an insulating resin. Examples of the resin material used for the base film 100 include polypropylene (PP), polyethylene terephthalate (PET), polyphenylene Sulfide (PPs), polyethylene naphthalate (PEN), polyarylate (PAR), polyphenylene ether (PPE), polyetherimide (PEI), and cyclic olefin polymer.

The metal plating layer 110 is formed on the surface of the base film 100 by vacuum vapor deposition, and examples of the metal material used for the metal plating layer 110 include aluminum, an alloy containing aluminum as a main component, and the like.

The direct-current support capacitor is mainly prepared through coating, slitting, winding, metal spraying, heat treatment, energization, assembly, encapsulation, aging and finished product measurement.

Coating: the metal is adhered on the base film to form a metallized film by adopting a vacuum evaporation mode under a certain vacuum degree, and the metallized film is the most core raw material of the metallized film capacitor, absorbs electric charge and further forms the capacitor. The metallized film has the main characteristics that: the low vacuum self-plating technology is adopted, and the plating vacuum degree is less than or equal to 4.0E ^-4 The sheet resistance of the active area is moderate, namely, the sheet resistance of the metal coating 110 is between 25 and 60 omega/≡can increase the current resistance, and meanwhile, compared with a conventional single-core structure, the double-core structure has the advantages that the film width of a single core is narrower, the overcurrent time can be reduced, the charge and discharge resistance and the ripple current resistance are improved, and the heat accumulated in high ripple current is less.

Slitting and winding: the metallized film is cut into required width by adopting a wave cutting mode and is wound into a cylindrical core, and the contact area of the metal spraying layer can be effectively improved by adopting wave cutting, so that the overcurrent capacity is increased and the product loss angle is reduced.

And (5) metal spraying: the metal spraying layer is two leading-out layers formed by driving metal particles with excellent conductivity into two end faces of a core formed by winding a metallized film through a spray gun, the direct-current support capacitor is made of pure zinc to form the metal spraying layer with the thickness of 1mm, wave cutting is combined, the conductivity is excellent, the cost is low, and the capacitor is guaranteed to generate little heat under the charge and discharge conditions.

And (3) assembling: the energized core is led out of the capacitor by a copper strip welding mode, the copper strip is mainly composed of red copper and tin, and the capacitor capacity is led out by welding, and the copper strips with different cross section areas have different overcurrent capacities due to heating in the conducting process. The direct current supporting capacitor of this application adopts 0.4X115 mm's tinned copper strips, and the copper strips is along core external connection, connects two copper strips symmetry of end cover both ends, and copper strips welded part is beaten a diameter and is 5mm via hole, and it is better to cross tin ability, simultaneously, connects the longest copper strips of two cores and adopts the double wiring design, has reduced the ESR of itself, and the overcurrent ability is good and generates heat less, is fit for mass production.

And (3) filling and sealing: the assembled semi-finished product casting resin mainly plays roles in protection, insulation and moisture prevention, and the direct-current support capacitor of the application adopts epoxy resin with good heat dissipation performance, and is low in cost and excellent in performance.

The dc support capacitor of the present application is further described below in connection with specific embodiments.

The production specification of the selected capacitor is as follows: 1100V600 mu F, size 116 x 110mm, the first example is a temperature rise product which is prepared by adopting different film width and copper strip connection modes, the first example is a conventional single-core product, the second example is a double-core product with the same film width, and the specific steps are as follows:

the electrical performance parameters of the first, comparative examples and comparative examples are as follows:

the application of 40A was maintained at 65℃for 48 hours, recorded every 1 hour for the last 6 hours, and the temperature rise data were as follows: embodiment one: the temperature units are all DEG C

Comparative example one: the temperature units are all DEG C

Comparative example two: the temperature units are all DEG C

From the above, the temperature rise of the first embodiment of the present application is optimal, and when the ripple current is 40A, the temperature rise of the first embodiment of the present application is 2.6-3.8 ℃ lower than that of the first comparative example, and 0.2-1.7 ℃ lower than that of the second comparative example.

Application of 60A at 65 ℃ for 48h, recording every 1h for the last 6h, and temperature rise data are as follows:

embodiment one: the temperature units are all DEG C

Comparative example one: the temperature units are all DEG C

Comparative example two: the temperature units are all DEG C

From the above, the temperature rise is also optimal in the first embodiment of the present application, and the temperature rise in the first embodiment of the present application is 8.2-9.6 ℃ lower than the temperature rise in the first comparative example and 3.8-4.7 ℃ lower than the temperature rise in the second comparative example when the ripple current is 60A.

Meanwhile, the products of the first embodiment and the first comparative example have the following pressure resistance:

base film withstand voltage of example one:

base film withstand voltage of comparative example one:

it can be seen that the first embodiment of the present application is not significantly different from the first comparative embodiment in terms of pressure resistance, and the different film width dual core designs of the present application can be used instead of the conventional single core design.

From the above description, it can be seen that the direct-current support capacitor has unique double-core structural design with different film widths, reduces the equivalent series resistance of the product, and is resistant to high current and high frequency; the core centering design is adopted, so that the stability of the electrical performance parameters is improved; the widened copper strips are adopted, so that the equivalent series resistance of the product is reduced, the heating copper strips are connected along the outside of the core, the heat dissipation capacity of the product is improved, and the internal temperature rise is reduced.

The relative arrangement of the components and steps, numerical expressions and numerical values set forth in these embodiments do not limit the scope of the present application unless it is specifically stated otherwise. Meanwhile, it should be understood that the sizes of the respective parts shown in the drawings are not drawn in actual scale for convenience of description. Techniques, methods, and apparatus known to one of ordinary skill in the relevant art may not be discussed in detail, but should be considered part of the specification where appropriate. In all examples shown and discussed herein, any specific values should be construed as merely illustrative, and not a limitation. Thus, other examples of the exemplary embodiments may have different values. It should be noted that: like reference numerals and letters denote like items in the following figures, and thus once an item is defined in one figure, no further discussion thereof is necessary in subsequent figures. In the description of the present application, it should be understood that, where azimuth terms such as "front, rear, upper, lower, left, right", "transverse, vertical, horizontal", and "top, bottom", etc., indicate azimuth or positional relationships generally based on those shown in the drawings, only for convenience of description and simplification of the description, these azimuth terms do not indicate and imply that the apparatus or elements referred to must have a specific azimuth or be constructed and operated in a specific azimuth, and thus should not be construed as limiting the scope of protection of the present application; the orientation word "inner and outer" refers to inner and outer relative to the contour of the respective component itself.

Spatially relative terms, such as "above … …," "above … …," "upper surface at … …," "above," and the like, may be used herein for ease of description to describe one device or feature's spatial location relative to another device or feature as illustrated in the figures. It will be understood that the spatially relative terms are intended to encompass different orientations in use or operation in addition to the orientation depicted in the figures. For example, if the device in the figures is turned over, elements described as "above" or "over" other devices or structures would then be oriented "below" or "beneath" the other devices or structures. Thus, the exemplary term "above … …" may include both orientations of "above … …" and "below … …". The device may also be positioned in other different ways (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly.

In addition, the terms "first", "second", etc. are used to define the components, and are merely for convenience of distinguishing the corresponding components, and unless otherwise stated, the terms have no special meaning, and thus should not be construed as limiting the scope of the present application. The above description is only of the preferred embodiments of the present utility model and is not intended to limit the present utility model, but various modifications and variations can be made to the present utility model by those skilled in the art. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present utility model should be included in the protection scope of the present utility model.

Claims

1. The direct current support capacitor is characterized by comprising a shell (1), wherein a first capacitor core (2) and a second capacitor core (3) are axially arranged in the shell (1);

the first capacitor core (2) and the second capacitor core (3) are connected in parallel, the first capacitor core (2) is close to a capacitor leading-out end, and the second capacitor core (3) is close to the bottom of the shell (1);

the first capacitor core (2) and the second capacitor core (3) are formed by winding at least two layers of metallized films, and the film width of the first capacitor core (2) is smaller than that of the second capacitor core (3).

2. Direct current support capacitor according to claim 1, characterized in that the first capacitive core (2) and the second capacitive core (3) are coaxially arranged.

3. The direct current support capacitor according to claim 1, characterized in that a first connection copper strip (4) and a second connection copper strip (5) are arranged in the housing (1);

the first connecting copper strips (4) and the second connecting copper strips (5) are symmetrically distributed along the periphery of the capacitor core;

the first connecting copper strip (4) is used for connecting two ends, which are away from each other, of the first capacitor core (2) and the second capacitor core (3) in parallel and then leading out the two ends;

the second connecting copper strip (5) is used for connecting two ends, close to each other, of the first capacitor core (2) and the second capacitor core (3) in parallel and then leading out the two ends.

4. A dc support capacitor according to claim 3, characterized in that the first connecting copper strips (4) are two.

5. A direct current support capacitor according to claim 3, characterized in that the housing (1) is a cylindrical housing with one end open, the open end of the housing (1) is provided with an end cover (6), and the end cover (6) is provided with a first lead-out terminal (7) and a second lead-out terminal (8);

the first capacitor core (2) is arranged close to the end cover (6);

the first connecting copper strip (4) is connected with the first lead-out terminal (7), and a through hole is formed in the end part of the first connecting copper strip (4) connected with the first lead-out terminal (7);

the second connecting copper strip (5) is connected with the second leading-out terminal (8), and a through hole is formed in the end portion, connected with the second leading-out terminal (8), of the second connecting copper strip (5).

6. Direct current support capacitor according to claim 5, characterized in that a potting compound (9) is arranged between the first and second capacitive cores (2, 3) and the housing (1).

7. The direct current support capacitor according to claim 5, characterized in that the end of the first capacitive core (2) near the end cap (6) is provided with a first insulating sleeve (10), and the end of the second capacitive core (3) near the housing (1) is provided with a second insulating sleeve (11).

8. The direct current support capacitor according to claim 1, characterized in that the metallized film comprises a base film (100) and a metal plating layer (110) provided on the base film (100);

the width of the base film (100) is larger than that of the metal plating layer (110), so that a clearance area (120) is formed on one side of the metallized film, and a wavy trimming edge (130) is formed on the other side of the metallized film opposite to the clearance area (120);

the wavy trimming edges (130) on two adjacent layers of the metallized films are respectively positioned at two ends of the capacitor core to be contacted with the metal spraying layers.

9. The direct current support capacitor according to claim 8, wherein the metal plating layer (110) is formed on the surface of the base film (100) by vacuum evaporation, and the plating vacuum degree is less than or equal to 4.0E ^-4 mbar。

10. The direct current support capacitor according to claim 9, characterized in that the sheet resistance of the metal plating layer (110) is 25 to 60 Ω/≡.