Metallized film for high voltage dry-type direct current support capacitor

Abstract

The utility model discloses a kind of metalized film for high-voltage dry-type direct-current support capacitor, metalized film is mainly composed of first layer metalized film, second layer metalized film, first layer metalized film is composed of first base film, first evaporation layer.Second layer metalized film is composed of second base film, second evaporation layer, first evaporation layer is composed of first edge thickening area, first active area, second active area, first intermediate screen belt, third active area, fourth active area, second edge thickening area, second evaporation layer is composed of first edge screen belt, fifth active area, sixth active area, seventh active area, second intermediate screen belt, eighth active area, second edge screen belt.The utility model is simple in structure, and in terms of manufacture, can satisfy high-voltage direct-current support capacitor high long-term safe and reliable operation.

Description

Technical Field

[0001] This utility model belongs to the field of metallized thin film technology, specifically relating to a metallized thin film for high-voltage dry DC support capacitors. 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 new energy, rail transportation, and smart grid sectors. These capacitors are characterized by their dry-type structure, high voltage rating, and large capacitance.

[0003] The rated voltage of the DC support capacitor depends on the IGBT device voltage of the converter power module. Currently, the main IGBT device voltage levels are 3300V and 4500V. In recent years, domestic and foreign research institutions and device manufacturers have conducted extensive research on high-voltage, high-power IGBT technology. Some manufacturers' IGBT devices have reached the 6000V / 2000A level. In addition, commercially available IGCT devices and IGBTs produced by domestic and foreign device manufacturers have reached the 6500V / 3000A level.

[0004] The rated voltage of the DC support capacitor for power modules with a device voltage rating of 3300V is 2.2~2.4kV. The rated voltage of the DC support capacitor for power modules with a device voltage rating of 4500V is 2.8~3.0kV. The rated voltage of the DC support capacitor for power modules with device voltage ratings of 6000V and 6500V is 3.8~4.0kV. The first two types of DC capacitors are widely used in converters in the fields of new energy, rail transit, and smart grids. Small-capacity 3.8~4.0kV DC capacitors are used in rail transit converters. Currently, large-capacity 3.8~4.0kV dry-type DC capacitors are still under development.

[0005] Currently, metallized film capacitors for DC supported capacitors with voltages ranging from 2.2 to 4.0 kV all employ a two-string internal structure, with a typical operating electric field strength of 233–240 V / μm. Due to limitations in film thickness, the thickness of the metallized film for this 2.2–4.0 kV DC supported capacitor configuration is somewhat restricted. For 2.2 kV DC supported capacitors, a 4.5 μm thick metallized film with a two-string internal structure is typically used, with an operating electric field strength of 244.4 V / μm. For 2.4 kV DC supported capacitors, a 5 μm thick metallized film with a two-string internal structure is typically used, with an operating electric field strength of 240 V / μm. For 2.8 kV DC supported capacitors, a 6 μm thick metallized film with a two-string internal structure is typically used, with an operating electric field strength of 233.3 V / μm. For 3.0 kV DC supported capacitors, a 6 μm thick metallized film with a two-string internal structure is typically used, with an operating electric field strength of 250 V / μm. DC supported capacitors with a voltage rating of 3.0kV typically use a 7μm thick metallized film with a two-string structure, and an operating electric field strength of 214.28V / μm. DC supported capacitors with a voltage rating of 3.8kV typically use an 8μm thick metallized film with a two-string structure, and an operating electric field strength of 237.5V / μm. DC supported capacitors with a voltage rating of 4kV typically use an 8μm thick metallized film with a two-string structure, and an operating electric field strength of 250V / μm. DC supported capacitors with a voltage rating of 4kV typically use a 9μm thick metallized film with a two-string structure, and an operating electric field strength of 222.2V / μm.

[0006] For capacitors at 3kV and 4kV voltage levels, the operating electric field strength varies greatly depending on the thickness of the metallized film. Higher operating electric field strength results in smaller dimensions but lower long-term reliability; conversely, lower operating electric field strength leads to larger dimensions but higher long-term reliability.

[0007] Document CN 108597866 A discloses a multi-internal-string structure metallized thin film, primarily targeting metallized power capacitors, especially metallized AC capacitors used for field compensation in high-voltage (AC2000V and above) applications, frequent voltage fluctuations, or severe overcurrent. Internally, it is equivalent to multiple capacitors connected in series, eliminating the need to fabricate ordinary metallized thin films into single capacitor cores and then connect several individual capacitor cores in series to form a complete capacitor. This not only saves costs and reduces processing steps but also results in a low product failure rate. The limitations of this technology are: the operating field strength of the metallized AC capacitor is 50~60V / μm; the three-internal-string structure in this technology requires thickening of each metallization layer, necessitating staggered edges during component winding, increasing the component length by 1~1.3mm. It is suitable for narrow films but less suitable for films with a width of 150μm.

[0008] Document CN 103366958A discloses a high-voltage metallized film capacitor, primarily targeting 10kV high-voltage power metering devices. This capacitor is an AC capacitor with a multi-segment internal series structure, featuring high output voltage, small size, and compact design. However, this technology has drawbacks: the multi-segment internal series structure of the high-voltage metallized film capacitor results in an effective electrode width of 2-4mm; the degree of misalignment during the winding of two metallized films affects the capacitance deviation and voltage division ratio; the sheet resistance of the electrodes is 7-10Ω / □, and its operating electric field strength is also relatively low.

[0009] Although the aforementioned multi-string metallized thin film has advantages such as high current density, small size, and reduced processing steps, its main features are low sheet resistance and low operating field strength, making it unsuitable for high voltage DC support capacitors with high operating field strength.

[0010] In summary, the key considerations for metallized thin films used in high-voltage DC supporting capacitors include: internal series structure; sheet resistance structure; film thickness; and operating field strength. Solving these key technologies is the crucial point that needs to be addressed in the research and development of this type of metallized thin film. Summary of the Invention

[0011] In order to overcome the shortcomings of existing metallized film technology for DC-supported capacitors, this invention proposes a metallized film for high-voltage dry-type DC-supported capacitors.

[0012] The technical solution adopted in this utility model is as follows.

[0013] This invention provides a metallized thin film for a high-voltage dry-type DC supported capacitor. The metallized thin film mainly consists of a first metallized thin film and a second metallized thin film. The first metallized thin film consists of a first base film and a first vapor-deposited layer. The second metallized thin film consists of a second base film and a second vapor-deposited layer.

[0014] The first vapor-deposited layer comprises a first edge thickened area, a first active area, a second active area, a first intermediate screen strip, a third active area, a fourth active area, and a second edge thickened area. The first edge thickened area is horizontally connected to the first active area, the first active area is horizontally connected to the second active area, the first intermediate screen strip is horizontally connected between the second and third active areas, the third active area is horizontally connected to the fourth active area, and the fourth active area is horizontally connected to the second edge thickened area.

[0015] The second vapor-deposited layer consists of a first edge strip, a fifth active area, a sixth active area, a seventh active area, a second intermediate strip, an eighth active area, and a second edge strip. The first edge strip is horizontally connected to the fifth active area, the sixth active area is horizontally connected between the fifth and seventh active areas, the second intermediate strip is horizontally connected between the seventh and eighth active areas, and the eighth active area is horizontally connected to the second edge strip.

[0016] After the first metallized film and the second metallized film are stacked, the first intermediate screen strip and the second intermediate screen strip will separate the first vapor-deposited layer and the second vapor-deposited layer for a second time, and are equivalent to a three-string structure with equal capacitance values.

[0017] The first base film is a high-temperature resistant electrical polypropylene film with a width of 100~150mm and a maximum working temperature of 110℃.

[0018] The second base film is a high-temperature resistant electrical polypropylene film with a width of 98~148mm and a maximum working temperature of 110℃.

[0019] The width of the first edge thickening area is 5mm, and the sheet resistance of the vapor-deposited metal layer is 2(1~3)Ω / □. Its material is zinc-aluminum alloy.

[0020] The sheet resistance of the metal layer vapor-deposited in the first active area is 7 (5~9) Ω / □, and its material is zinc-aluminum alloy.

[0021] The sheet resistance of the metal layer vapor-deposited in the second active area is 50 (40~60) Ω / □, and its material is zinc-aluminum alloy.

[0022] The width of the first intermediate screen is 5mm.

[0023] The sheet resistance of the metal layer vapor-deposited in the third active area is 50 (40~60) Ω / □, and its material is zinc-aluminum alloy.

[0024] The sheet resistance of the metal layer vapor-deposited in the fourth active zone is 7 (5~9) Ω / □, and its material is zinc-aluminum alloy.

[0025] The second edge thickening area has a width of 5mm, and the sheet resistance of the vapor-deposited metal layer is 2 (1~3) Ω / □. Its material is zinc-aluminum alloy.

[0026] The width of the first edge screen band is 2.5~3mm.

[0027] The sheet resistance of the metal layer vapor-deposited in the fifth active zone is 50 (40~60) Ω / □, and its material is zinc-aluminum alloy.

[0028] The sheet resistance of the metal layer vapor-deposited in the sixth active zone is 7 (5~9) Ω / □, and its material is zinc-aluminum alloy.

[0029] The sheet resistance of the metal layer vapor-deposited in the seventh active area is 50 (40~60) Ω / □, and its material is zinc-aluminum alloy.

[0030] The width of the second intermediate screen is 5mm.

[0031] The sheet resistance of the metal layer vapor-deposited in the eighth active zone is 40 (30~50) Ω / □, and its material is zinc-aluminum alloy.

[0032] Furthermore, the first base film is 2mm wider than the second base film, and both have the same thickness and material. Under special operating conditions, they can also have different thicknesses.

[0033] Furthermore, the width of the first active area accounts for approximately 10% of the width of the first base film, the width of the second active area accounts for approximately 28% of the width of the first base film, the width of the third active area accounts for approximately 51% of the width of the first base film, and the width of the fourth active area accounts for approximately 10% of the width of the first base film.

[0034] Furthermore, the width of the fifth active region accounts for approximately 25% of the width of the first base film, the width of the sixth active region accounts for approximately 19% of the width of the first base film, the width of the seventh active region accounts for approximately 25% of the width of the first base film, and the width of the eighth active region accounts for approximately 30% of the width of the first base film.

[0035] The beneficial effects of this invention are: in addition to having the advantages of high current density, small size, and reduced processing steps of the metallized thin film with inner string structure, the thin metallized thin film with three inner string structures can achieve a capacitor working field strength of 240V / µm, reduce the size of the capacitor, and improve its self-healing properties.

[0036] This invention has a simple structure and is easy to manufacture, and can meet the requirements for high long-term safe and reliable operation of high voltage DC support capacitors. Attached Figure Description

[0037] Figure 1 This is a schematic diagram of the present invention;

[0038] Figure 2 This is a side view of the first metallized thin film;

[0039] Figure 3 This is a side view of the second metallized thin film;

[0040] Figure 4 The equivalent circuit diagram for the application of this utility model;

[0041] 11-First base film; 12-First vapor-deposited layer;

[0042] 21-Second base film; 22-Second vapor-deposited layer;

[0043] 121 - First edge thickening area; 122 - First active area; 123 - Second active area; 124 - First intermediate screen strip; 125 - Third active area; 126 - Fourth active area; 127 - Second edge thickening area;

[0044] 221 - First edge screen strip; 222 - Fifth active area; 223 - Sixth active area; 224 - Seventh active area; 225 - Second middle screen strip; 226 - Eighth active area; 227 - Second edge screen strip. Detailed Implementation

[0045] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0046] exist Figure 1 As can be seen, the metallized film for high-voltage dry DC supported capacitors is mainly composed of a first metallized film (1) and a second metallized film (2); the first metallized film (1) is composed of a first base film (11) and a first vapor deposition layer (12); the second metallized film (2) is composed of a second base film (21) and a second vapor deposition layer (22).

[0047] exist Figure 2 As can be seen, the first vapor-deposited layer (12) is composed of a first edge thickening area (121), a first active area (122), a second active area (123), a first intermediate screen strip (124), a third active area (125), a fourth active area (126), and a second edge thickening area (127). The first edge thickening area (121) is horizontally connected to the first active area (122), the first active area (122) is horizontally connected to the second active area (123), the first intermediate screen strip (124) is horizontally connected between the second active area (123) and the third active area (125), the third active area (125) is horizontally connected to the fourth active area (126), and the fourth active area (126) is horizontally connected to the second edge thickening area (127).

[0048] exist Figure 3 As can be seen, the second vapor-deposited layer (22) is composed of a first edge screen (221), a fifth active area (222), a sixth active area (223), a seventh active area (224), a second intermediate screen (225), an eighth active area (226), and a second edge screen (227). The first edge screen (221) is horizontally connected to the fifth active area (222), the sixth active area (223) is horizontally connected between the fifth active area (222) and the seventh active area (224), the second intermediate screen (225) is horizontally connected between the seventh active area (224) and the eighth active area (226), and the eighth active area (226) is horizontally connected to the second edge screen (227).

[0049] exist Figure 4 As can be seen: when the first metallized film (1) and the second metallized film (2) are stacked, the first intermediate screen strip (124) and the second intermediate screen strip (225) will separate the first vapor deposition layer (1) and the second vapor deposition layer (2) twice, and are equivalent to a three-string structure with equal capacitance values.

[0050] The first base film (11) is a high-temperature resistant electrical polypropylene film with a width of 100~150mm and a maximum working temperature of 110℃.

[0051] The second base film (21) is a high-temperature resistant electrical polypropylene film with a width of 98~148mm and a maximum working temperature of 110℃.

[0052] The width of the first edge thickened area (121) is 5mm, and the sheet resistance of the vapor-deposited metal layer is 2 (1~3)Ω / □. Its material is zinc-aluminum alloy.

[0053] The sheet resistance of the metal layer vapor-deposited in the first active area (122) is 7 (5~9) Ω / □, and its material is zinc-aluminum alloy.

[0054] The sheet resistance of the metal layer vapor-deposited in the second active area (123) is 50 (40~60) Ω / □, and its material is zinc-aluminum alloy.

[0055] The width of the first intermediate screen strip (124) is 5mm.

[0056] The sheet resistance of the metal layer vapor-deposited in the third active area (125) is 50 (40~60) Ω / □, and its material is zinc-aluminum alloy.

[0057] The sheet resistance of the metal layer vapor-deposited in the fourth active area (126) is 7 (5~9) Ω / □, and its material is zinc-aluminum alloy.

[0058] The second edge thickening area (127) has a width of 5 mm, and the sheet resistance of the vapor-deposited metal layer is 2 (1~3) Ω / □. Its material is zinc-aluminum alloy.

[0059] The width of the first edge screen strip (221) is 2.5~3mm.

[0060] The sheet resistance of the metal layer vapor-deposited in the fifth active area (222) is 50 (40~60) Ω / □, and its material is zinc-aluminum alloy.

[0061] The sheet resistance of the metal layer vapor-deposited in the sixth active area (223) is 7 (5~9) Ω / □, and its material is zinc-aluminum alloy.

[0062] The sheet resistance of the metal layer vapor-deposited in the seventh active area (224) is 50 (40~60) Ω / □, and its material is zinc-aluminum alloy.

[0063] The width of the second intermediate screen strip (225) is 5mm.

[0064] The sheet resistance of the metal layer vapor-deposited in the eighth active area (226) is 40 (30~50) Ω / □, and its material is zinc-aluminum alloy.

[0065] The width of the second edge screen strip (227) is 2.5~3mm.

[0066] Furthermore, the first base film (11) is 2 mm wider than the second base film (21), and both have the same thickness and material. Under special operating conditions, they can also have different thicknesses.

[0067] Furthermore, the width of the first active area (122) is about 10% of the width of the first base film (11), the width of the second active area is about 28% of the width of the first base film (11), the width of the third active area is about 51% of the width of the first base film (11), and the width of the fourth active area (11) is about 10% of the width of the first base film.

[0068] Furthermore, the width of the fifth active region (222) is about 25% of the width of the second base film (21), the width of the sixth active region (223) is about 19% of the width of the second base film (21), the width of the seventh active region (224) is about 25% of the width of the second base film (21), and the width of the eighth active region (226) is about 30% of the width of the second base film (21).

[0069] 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 metallized thin film for a high-voltage dry-type DC supported capacitor, characterized in that: The metallized thin film mainly consists of a first metallized thin film and a second metallized thin film. The first metallized thin film consists of a first base film and a first vapor deposition layer, and the second metallized thin film consists of a second base film and a second vapor deposition layer. The first vapor-deposited layer is composed of a first edge thickening area, a first active area, a second active area, a first intermediate screen strip, a third active area, a fourth active area, and a second edge thickening area. The first edge thickening area is horizontally connected to the first active area, the first active area is horizontally connected to the second active area, the first intermediate screen strip is horizontally connected between the second active area and the third active area, the third active area is horizontally connected to the fourth active area, and the fourth active area is horizontally connected to the second edge thickening area. The second vapor-deposited layer is composed of a first edge screen strip, a fifth active area, a sixth active area, a seventh active area, a second intermediate screen strip, an eighth active area, and a second edge screen strip. The first edge screen strip is horizontally connected to the fifth active area, the sixth active area is horizontally connected between the fifth and seventh active areas, the second intermediate screen strip is horizontally connected between the seventh and eighth active areas, and the eighth active area is horizontally connected to the second edge screen strip. After the first metallized film and the second metallized film are stacked, the first intermediate screen strip and the second intermediate screen strip will separate the first vapor deposition layer and the second vapor deposition layer a second time and simultaneously be equivalent to a three-string structure.

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