A new energy vehicle-mounted frequency converter electromagnetic interference suppression capacitor

Abstract

The utility model provides a new energy vehicle-mounted frequency converter electromagnetic interference suppression capacitor, including from outside to inside are equipped with double -deck electromagnetic shield cover, shell, core in proper order, double -deck electromagnetic shield cover is by permalloy inner layer and aluminium alloy outer layer is made of conductive glue compound, the capacitor core that core is by two different thicknesses metallized polypropylene film is coiled, and the edge of metallized polypropylene film is equipped with gradual change evaporation area, and the both ends of core are provided with the gold -spraying layer respectively, and the gold -spraying layer and the metal layer of metallized film form ohmic contact, and the copper plating tin lead-out terminal is connected with the gold -spraying layer of both ends of core through laser welding, and the empty region between shell inside and core is filled with epoxy resin, the utility model has the advantages of: through the cooperation of double -deck metallized film and gradual change evaporation area, significantly reduces the edge electric field concentration, improves partial discharge voltage, and laser welding terminal makes the contact resistance reduce, reduces ESR, and the overall ESL reduces, and can directly replace a plurality of parallel small -capacity capacitors.

Description

Technical Field

[0001] This utility model belongs to the field of capacitor technology, and is particularly suitable for an electromagnetic interference suppression capacitor for a new energy vehicle frequency converter. Background Technology

[0002] As the power density of electric drive systems in new energy vehicles continues to increase and the switching speed of IGBT / SiC MOSFETs accelerates, DC bus voltage ripple and electromagnetic interference (EMI) problems are becoming increasingly prominent. Although traditional aluminum electrolytic capacitors have large capacitance, they suffer from high ESR, low temperature resistance, and short lifespan. While ordinary metallized film capacitors offer advantages such as low ESR and long lifespan, they lack sufficient EMI suppression capabilities at high frequencies, and are prone to film breakdown and capacitance drift due to vehicle vibration and high-temperature environments. Utility Model Content

[0003] To address the above shortcomings, the purpose of this utility model is to provide an electromagnetic interference suppression capacitor for new energy vehicle inverters, which has high thermal conductivity, high shielding, and low ESR / ESL characteristics, making it particularly suitable for use in new energy vehicle inverters.

[0004] The technical solution of this utility model is: an electromagnetic interference suppression capacitor for a new energy vehicle inverter, comprising, from the outside to the inside, a double-layer electromagnetic shield, an outer shell, and a core. The double-layer electromagnetic shield is composed of a permalloy inner layer and an aluminum alloy outer layer bonded together with conductive adhesive. The double-layer electromagnetic shield is bonded to the outer shell with conductive adhesive. The outer shell is an aluminum alloy shell, and the inner wall of the aluminum alloy shell is covered with a thermally conductive insulating layer of aluminum nitride-filled silicone rubber. The core is a capacitor core made of two metallized polypropylene films of different thicknesses wound together. The edges of the metallized polypropylene films are provided with gradient vapor deposition areas. Gold spraying layers are respectively provided at both ends of the core. The gold spraying layers and the metal layers of the metallized films form ohmic contacts. Copper-plated tin leads are connected to the gold spraying layers at both ends of the core by laser welding. The empty area between the outer shell and the core is filled with epoxy resin.

[0005] Furthermore, the thickness of the thermally conductive insulating layer is 0.5 mm to 1.5 mm.

[0006] Furthermore, the metal layer of the metallized polypropylene film is a zinc-aluminum alloy.

[0007] Furthermore, the metal layer thickness of one metallized polypropylene film is 20 nm to 50 nm, and the metal layer thickness of the other metallized polypropylene film is 60 nm to 100 nm.

[0008] Furthermore, the metallized polypropylene film has a gradient vapor deposition region extending along the width direction of the film at the edge of the metal layer, and the sheet resistance of the gradient vapor deposition region gradually increases in the direction away from the edge of the metal layer.

[0009] Furthermore, the gold plating layer is a zinc-copper alloy gold plating layer.

[0010] Furthermore, the width of the gradient evaporation zone is 1 mm to 3 mm, and the sheet resistance gradient of the gradient evaporation zone is 10 Ω / mm to 50 Ω / mm.

[0011] The advantages and positive effects of this utility model are as follows: By adopting the above technical solution, the edge electric field concentration is significantly reduced and the partial discharge voltage is improved through the synergy of the double-thickness metallized film and the gradient evaporation zone; the double-layer permalloy + aluminum alloy shield provides ≥60dB insertion loss in the 150 kHz to 30 MHz frequency band, which is an improvement over the single-layer aluminum shield; the aluminum nitride-filled silicone rubber thermally conductive insulating layer reduces thermal resistance; the laser-welded terminals reduce contact resistance and ESR; the overall ESL is reduced, and it can directly replace multiple parallel small-capacity capacitors. Attached Figure Description

[0012] Figure 1 This is a schematic diagram of the structure of this utility model.

[0013] Figure 2 This is a schematic diagram of the core structure.

[0014] In the picture: 1. Double-layer electromagnetic shielding cover; 2. Outer shell; 3. Core. 4. Thermally conductive insulating layer; 5. Metallized polypropylene film; 6. Gold sputtering layer. 7. Tin-plated copper leads; 8. Epoxy resin; 9. Gradient vapor deposition area. Detailed Implementation

[0015] like Figure 1 , 2 As shown, the technical solution of this utility model is an electromagnetic interference suppression capacitor for a new energy vehicle frequency converter, comprising, from the outside to the inside, a double-layer electromagnetic shielding cover 1, an outer shell 2, and a core 3. The double-layer electromagnetic shielding cover 1 is composed of a permalloy inner layer and an aluminum alloy outer layer bonded together with conductive adhesive. The double-layer electromagnetic shielding cover 1 and the outer shell 2 are bonded together with conductive adhesive. The outer shell 2 is an aluminum alloy shell, and the inner wall of the aluminum alloy shell is covered with a thermally conductive insulating layer 4 of aluminum nitride-filled silicone rubber. The core 3 is formed by winding at least two layers of metallized polypropylene film 5, wherein the metal layer thickness of one layer of metallized polypropylene film 5 is 20 nm to 50 nm, the metal layer thickness of the other layer of metallized polypropylene film 5 is 60 nm to 100 nm, and the difference in metal layer thickness between the two layers of metallized polypropylene film 5 is ≥30 nm; a gradient vapor deposition area extending along the width direction of the metal layer of the metallized polypropylene film 5 is provided at the edge of the metal layer, and the sheet resistance of the gradient vapor deposition area continuously increases from 0.1 Ω to 100 Ω in the direction away from the edge of the metal layer; a gold sputtering layer 6 is provided at both ends of the capacitor core 3, and the gold sputtering layer 6 forms an ohmic contact with the metal layer of the metallized film; copper-plated tin lead terminals 7 are connected to the gold sputtering layers 6 at both ends of the core 3 by laser welding; and epoxy resin 8 is potted in the empty area between the shell 1 and the core 3.

[0016] In this embodiment, the thickness of the thermally conductive insulating layer 4 is 0.5 mm to 1.5 mm.

[0017] In this embodiment, the metal layer of the metallized polypropylene film 5 is a zinc-aluminum alloy.

[0018] In this embodiment, the gold plating layer 6 is a zinc-copper alloy gold plating layer.

[0019] In this embodiment, the width of the gradient vapor deposition area is 1 mm to 3 mm, and the sheet resistance of the gradient vapor deposition area changes from 10 Ω / mm to 50 Ω / mm.

[0020] The working process of this example is as follows: When in use, the capacitor is fixed to the DC bus of the new energy vehicle inverter with bolts. The torque of the bolts is 1.5 N·m to 2.5 N·m, and a spring washer is provided between the bolt and the capacitor shell. The capacitor is connected in parallel between the positive and negative terminals of the DC bus of the inverter to suppress the electromagnetic interference generated by the inverter.

[0021] The above description provides a detailed account of one embodiment of the present invention. However, this description is merely a preferred embodiment and should not be construed as limiting the scope of the present invention. All equivalent variations and improvements made within the scope of the claims of the present invention should still fall within the patent coverage of the present invention.

Claims

1. A capacitor for suppressing electromagnetic interference in a new energy vehicle frequency converter, characterized in that: The device comprises, from the outside in, a double-layer electromagnetic shield, an outer shell, and a core. The double-layer electromagnetic shield is composed of a permalloy inner layer and an aluminum alloy outer layer bonded together with conductive adhesive. The double-layer electromagnetic shield is bonded to the outer shell with conductive adhesive. The outer shell is made of aluminum alloy, and its inner wall is covered with a thermally conductive insulating layer of aluminum nitride-filled silicone rubber. The core is a capacitor core made of two metallized polypropylene films of different thicknesses wound together. The edges of the metallized polypropylene films have gradient vapor-deposited areas, and gold-plated layers are respectively provided at both ends of the core. The gold-plated layers form ohmic contacts with the metal layers of the metallized films. Copper-plated tin leads are connected to the gold-plated layers at both ends of the core by laser welding. The empty area between the core and the outer shell is filled with epoxy resin.

2. The electromagnetic interference suppression capacitor for a new energy vehicle on-board frequency converter according to claim 1, characterized in that: The thickness of the thermally conductive insulating layer is 0.5 mm to 1.5 mm.

3. The electromagnetic interference suppression capacitor for a new energy vehicle on-board frequency converter according to claim 1, characterized in that: The metal layer of the metallized film is a zinc-aluminum alloy.

4. The electromagnetic interference suppression capacitor for a new energy vehicle on-board frequency converter according to claim 1, characterized in that: The metal layer of one metallized polypropylene film has a thickness of 20 nm to 50 nm, and the metal layer of the other metallized polypropylene film has a thickness of 60 nm to 100 nm.

5. The electromagnetic interference suppression capacitor for a new energy vehicle on-board frequency converter according to claim 1, characterized in that: The metallized polypropylene film has a gradient vapor deposition region extending along the width direction of the film at the edge of the metal layer, and the sheet resistance of the gradient vapor deposition region gradually increases in the direction away from the edge of the metal layer.

6. The electromagnetic interference suppression capacitor for a new energy vehicle on-board frequency converter according to claim 1, characterized in that: The gold plating layer is a zinc-copper alloy gold plating layer.

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