A high-voltage charging pile transformer and a high-voltage charging pile

Abstract

The utility model discloses a high -pressure charging stake transformer, include: winding subassembly, including first winding support part and second winding support part, be provided with first coil on the first winding support part, the first winding support part includes first through cavity, be provided with second coil on the second winding support part, the second winding support part includes second through cavity, the second winding support part passes through the first winding support part and is accommodated with the second through cavity, the shell is sleeved in the second winding support part outside, and the shell is formed with first clearance area between the second winding support part, and the first clearance area is filled with insulating material, at least two magnetic cores, the magnetic core is equipped with with the concave -convex structure of one side cooperation of first winding support part and second winding support part, is used for increasing the creepage distance, through the synergistic effect of mechanical range increasing and material thickening, effectively solved the partial discharge problem under high electric field intensity.

Description

Technical Field

[0001] This utility model relates to the field of ultra-fast charging technology for new energy vehicles, and in particular to a high-voltage charging pile transformer and a high-voltage charging pile. Background Technology

[0002] High-voltage charging piles are core equipment for the rapid charging of new energy vehicles, and the isolation transformer is a key component for achieving power conversion and isolation. With the continuous increase in charging pile power and voltage levels (such as 1500V systems), the electric field strength inside the transformer increases dramatically, posing a severe challenge to insulation reliability. Existing high-voltage charging pile transformers have shortcomings in dielectric strength and partial discharge performance. Partial discharge is particularly significant under high voltage and is one of the main causes of insulation material aging, breakdown, and ultimately equipment failure. Therefore, a new transformer insulation structure is urgently needed, which, through optimized design, can significantly improve its dielectric strength and ability to suppress partial discharge, to meet the stringent reliability and safety requirements of next-generation high-voltage fast charging piles. Utility Model Content

[0003] The purpose of this invention is to provide an insulation structure for a high-voltage charging pile transformer, which can synergistically improve the body insulation strength and surface withstand voltage, thereby fundamentally solving the insulation reliability problem under high electric field strength.

[0004] The technical problem of this utility model is solved by the following technical solution: In a first aspect, this utility model provides a high-voltage charging pile transformer, comprising: A winding assembly includes a first winding support portion and a second winding support portion. A first coil is disposed on the first winding support portion and the first winding support portion includes a first through cavity. A second coil is disposed on the second winding support portion and the second winding support portion includes a second through cavity. The second winding support portion accommodates the first winding support portion through the second through cavity. The outer shell is fitted onto the outside of the second winding support, and a first gap area is formed between the outer shell and the second winding support, and the first gap area is filled with insulating material. At least two magnetic cores, each core having a concave-convex structure that mates with one side of the first winding support and the second winding support to increase the creepage distance.

[0005] In some embodiments, the following technical features are also included: The concave-convex structure is a stepped groove in the shape of a zigzag, specifically including a central extension and side extensions located on both sides of the central extension. The central extension is accommodated at one end of the first through cavity, and the side extensions are attached to the outer wall of the outer shell.

[0006] In some embodiments, a second gap region is formed between the first winding support portion and the second winding support portion, and the second gap region is filled with insulating material.

[0007] In some embodiments, the insulating material includes epoxy resin.

[0008] In some embodiments, the thickness of the first gap region is greater than or equal to 1.5 mm, and the thickness of the second gap region is 0.5-2 mm.

[0009] In some embodiments, the first winding support portion and the second winding support portion are made of flame-retardant polyethylene terephthalate.

[0010] In some embodiments, the thickness of the first winding support portion and the second winding support portion is 2-5 mm.

[0011] In some embodiments, a retaining strap is also included for securing the magnetic core assembly to the housing.

[0012] In some embodiments, a base is also included, which is connected to one end of the fixing strap.

[0013] Secondly, this utility model provides a high-voltage charging pile, which includes the aforementioned high-voltage charging pile transformer.

[0014] The beneficial effects of this utility model compared with the prior art include: This invention constructs a composite insulation system by incorporating a first and second winding support with nested structures, forming a first gap region filled with insulating material between the support and the outer shell. Simultaneously, a mating surface with an uneven structure is provided for the magnetic core. This system effectively increases the surface creepage distance between components at different potentials through the mechanical design of the uneven structure, thus extending the mechanical range and suppressing surface discharge. Furthermore, by filling the gap region with insulating material, the insulation thickness is increased, eliminating air gaps and significantly improving the bulk insulation strength. The mechanical range extension and material thickening complement each other and work synergistically to fundamentally improve insulation reliability, thereby significantly enhancing the withstand voltage of the entire transformer insulation structure and effectively solving the problem of partial discharge under high electric field strength.

[0015] Other beneficial effects of the embodiments of this utility model will be further described below. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the overall structure of the high-voltage charging pile transformer in this embodiment of the utility model.

[0017] Figure 2 This is an exploded view of the high-voltage charging pile transformer in an embodiment of this utility model.

[0018] Figure 3 This is a cross-sectional schematic diagram of the overall structure of the high-voltage charging pile transformer in this embodiment of the present invention.

[0019] Figure 4 This is a schematic diagram of the zigzag stepped groove on the magnetic core assembly in an embodiment of this utility model.

[0020] Figure 5 This is a schematic diagram of the structure after the winding assembly is nested in an embodiment of this utility model.

[0021] Figure label: 1. Primary frame; 2. Secondary frame; 3. Primary coil; 4. Secondary coil; 5. Magnetic core; 51. Central extension; 52. Side extension; 6. Fixing steel strip; 7. Base; 8. Housing; 9. Lead-out slot; 10. Lead-out terminal; 11. First gap area; 12. Second gap area. Detailed Implementation

[0022] The present invention will be further described below with reference to the accompanying drawings and preferred embodiments. It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other.

[0023] Conceptual Design: The core of this invention lies in optimizing the insulation structure of a high-voltage charging pile transformer through a dual-path strategy of "mechanical range extension" and "material thickening." Specifically, an independent potting cavity (second gap region) is formed by a nested winding support section, and another potting cavity (first gap region) is formed between its exterior and the outer shell. Combined with a special concave-convex structure on the magnetic core (such as a stepped groove), the creepage distance is significantly increased. Finally, a robust insulation barrier is formed by potting insulating materials (such as epoxy resin, silicone gel, polyurethane potting compound, etc.), jointly overcoming the insulation reliability problem under high power density.

[0024] Therefore, this utility model embodiment provides a high-voltage charging pile transformer, comprising: A winding assembly includes a first winding support and a second winding support. A first coil is disposed on the first winding support and the first winding support includes a first through cavity. A second coil is disposed on the second winding support and the second winding support includes a second through cavity. The second winding support accommodates the first winding support through the second through cavity. A housing is fitted over the second winding support, and a first gap region is formed between the housing and the second winding support. The first gap region is filled with insulating material. At least two magnetic cores are provided with concave-convex structures that mate with one side of the first winding support and the second winding support to increase the creepage distance.

[0025] The following specific examples will provide further details.

[0026] Example 1 This embodiment provides a high-voltage charging pile transformer. In this embodiment, the first winding support is specifically defined as a primary frame 1, the second winding support is specifically defined as a secondary frame 2, the first coil is specifically defined as a primary coil 3, the second coil is specifically defined as a secondary coil 4, and the fixing strip is specifically defined as a fixing steel strip 6.

[0027] See Figure 1-5 The high-voltage charging pile transformer includes a primary frame 1, a secondary frame 2, a primary coil 3, a secondary coil 4, a magnetic core 5, a fixing steel strip 6, a base 7, a housing 8, lead-out slots 9, and lead-out terminals 10. The primary frame 1 is made of flame-retardant polyethylene terephthalate (PET FR530), and has a first through-cavity with a wall thickness of 3.25 mm. The long-term service temperature rating of the flame-retardant PET material is not lower than 130℃ to adapt to the transformer's operating temperature and the curing temperature of the epoxy resin. The secondary frame 2 is also made of PET FR530, and has a second through-cavity with a wall thickness of 2-5 mm, preferably 3.25 mm. The dimensions of this second through-cavity are designed to accommodate the primary frame 1 with the primary coil 3 already wound, forming a nested structure. The primary coil 3 is wound on the primary frame 1, and its specifications are FLW-F 0.1mm 450P 36TS. The secondary coil 4 is wound on the secondary bobbin 2, and its specifications are 2UEW-H 0.1mm 400*2P 24TS. The outer shell 8 is fitted over the secondary bobbin 2, which has the secondary coil 4 already nested inside. Figure 3As shown, a first gap region 11 is formed between the inner wall of the outer shell 8 and the outer wall of the secondary frame 2. The thickness of this region is designed to be ≥1.5mm, with a tolerance of ±0.1mm. A second gap region 12 is formed between the primary frame 1 and the secondary frame 2. The thickness of this region is 0.5mm to 2mm, with a tolerance of ±0.1mm, preferably 1.0mm. The magnetic core 5 is a ferrite core, and both cores have a stepped groove-like concave-convex structure. Figure 4 As shown, the concave-convex structure includes a central extension 51 and two side extensions 52. During assembly, the central extension 51 extends into and is accommodated at one end of the first through cavity of the primary frame 1, while the two side extensions 52 are fitted against the corresponding outer walls of the housing 8. A fixing steel strip 6 is used to firmly fix the two magnetic cores 5 to the housing 8. The base 7 is connected to one end of the fixing steel strip 6 by welding or screws. The wire end of the secondary coil 4 extends upward to form a lead-out terminal 10, and the lead-out groove 9 has a through hole in the middle for the lead-out terminal 10 to pass through and fit against and fix to the upper part of the housing 8. The thickness design of the first gap region and the second gap region is determined based on the electric field simulation results under the working voltage to ensure that the electric field strength between each insulating layer is lower than the allowable field strength of the insulating material used.

[0028] Working principle: Current flows through the lead-out terminal 10 into the secondary coil 4 and the primary coil 3, generating an alternating magnetic field in the magnetic circuit formed by the magnetic core 5, thus completing the transmission of electrical energy and voltage conversion. During this process, reliable physical isolation and insulation are achieved between the primary coil (high-voltage side) and the secondary coil (low-voltage side) through a 3.25mm thick skeleton wall, a potted insulation layer in the second gap region, and a potted insulation layer in the first gap region. The Z-shaped stepped groove structure on the magnetic core 5 forces the current to follow a longer tortuous path (i.e., creepage distance) to form a path between the high-voltage primary side and the low-voltage secondary side, greatly improving the surface withstand voltage and effectively suppressing partial discharge.

[0029] Implementation steps: Fabrication of winding jig: A special winding jig is fabricated based on the three-dimensional structure of the primary skeleton 1 and the secondary skeleton 2.

[0030] Winding the primary coil: Use a winding machine to wind wires of the specified specifications onto the primary bobbin 1.

[0031] Winding the secondary coil: Use a winding machine to wind wires of the specified specifications onto the secondary bobbin 2.

[0032] Assemble the winding assembly: Nest the primary bobbin 1 with the primary coil 3 wound inside the second through cavity of the secondary bobbin 2 with the secondary coil 4 wound inside.

[0033] Assemble the outer casing: Place the outer casing 8 over the assembly assembled in step 4, and fill the first gap area between the outer casing 8 and the secondary frame 2 with epoxy resin. The epoxy resin is made of epoxy resin with a viscosity of 2000-5000 mPa·s at 25°C to ensure good flowability and filling properties; the thermal conductivity after curing is not less than 0.8 W / (m·K) to facilitate heat dissipation of the transformer.

[0034] Assemble and fix the magnetic core: Insert the central extension 51 of the two magnetic cores 5 into the first through cavity of the primary skeleton 1 from both ends, and fix the magnetic core 5 to the outer shell 8 with the fixing steel strip 6. Connect the base 7 to the fixing steel strip 6.

[0035] Install the lead wire assembly: Pass the lead wire terminal 10 through the through hole of the lead wire groove 9 and secure it.

[0036] Vacuum potting: After assembling all mechanical structures (winding assembly, housing, magnetic core, fixing strip), the entire transformer assembly is placed in a vacuum potting machine. During a single vacuuming and potting operation, the epoxy resin in the first gap area and the second gap area is filled simultaneously, ensuring that the filling is thorough and free of air bubbles.

[0037] Curing and molding: Place the potted product in an oven to allow the epoxy resin to cure and solidify.

[0038] Example 2 The difference between this embodiment and Embodiment 1 is that it further defines the specific shape of the concave and convex structure on the magnetic core.

[0039] In this embodiment, the concave-convex structure is specifically defined as a stepped groove in the shape of a zigzag.

[0040] Based on the structure of Embodiment 1, the concave-convex structure on the magnetic core 5 in this embodiment is specifically a stepped groove in the shape of a zigzag. For example... Figure 4 As shown, this structure is formed on the end face of the magnetic core 5 through precision machining. The width of the central extension 51 matches the inner diameter of the first through cavity of the primary frame 1, and the contour of the side extension 52 fits the curvature of the outer wall of the outer shell 8.

[0041] By setting a specific zigzag stepped groove structure, the surface path length of the mating area between the magnetic core and the frame and shell is maximized. This is a key design for realizing the "mechanical range extension" strategy and can more effectively suppress surface discharge and arcing.

[0042] Example 3 The difference between this embodiment and Embodiment 1 is that it further optimizes the insulation filling strategy.

[0043] Based on the structure of Embodiment 1, in this embodiment, the second gap region 12 formed after the primary skeleton 1 and the secondary skeleton 2 are nested is also potted with epoxy resin, such as... Figure 3 As shown.

[0044] By adding potting between the main and slave frames, all air gaps in this area are eliminated, the potential risk of partial discharge is completely sealed off, and the heat dissipation path of the transformer is improved.

[0045] Example 4 The difference between this embodiment and Embodiment 1 is that it further adds a fixing structure.

[0046] Based on the structure of Embodiment 1, the fixing steel strip 6 in this embodiment is made of 304 stainless steel strip, which is bundled onto the magnetic core 5 and the outer shell 8 by a set of tensioning clamps, and the two ends are riveted or welded together. The base 7 is an aluminum die-cast part, which is provided with mounting holes and is connected and fixed to the bent end of the fixing steel strip 6 by screws.

[0047] The fixing strap and base provide mechanical stability and a mounting foundation for the connection between the magnetic core and the housing, preventing the magnetic core from shifting due to electromagnetic force or vibration, and ensuring the structural stability of the product during long-term operation.

[0048] This utility model provides an isolation transformer insulation structure for 800V-1500V DC fast charging piles, featuring innovative designs for ferrite cores, multi-layer winding bobbin systems, and detachable insulation components. This solves the insulation reliability problem under high power density, increasing the withstand voltage from 5KV to 50KV and reducing the partial discharge from 25Pc (picocells) to below 5Pc. Furthermore, the use of flame-retardant polyethylene terephthalate (PET) for the winding support further enhances the product's safety and flame-retardant properties.

[0049] The above description, in conjunction with specific preferred embodiments, provides a further detailed explanation of the present invention. It should not be construed that the specific implementation of the present invention is limited to these descriptions. For those skilled in the art, several equivalent substitutions or obvious modifications can be made without departing from the concept of the present invention, and all such modifications, with identical performance or use, should be considered within the protection scope of the present invention.

Claims

1. A high-voltage charging pile transformer, characterized in that, include: A winding assembly includes a first winding support portion and a second winding support portion. A first coil is disposed on the first winding support portion and the first winding support portion includes a first through cavity. A second coil is disposed on the second winding support portion and the second winding support portion includes a second through cavity. The second winding support portion accommodates the first winding support portion through the second through cavity. The outer shell is fitted onto the outside of the second winding support, and a first gap area is formed between the outer shell and the second winding support, and the first gap area is filled with insulating material. At least two magnetic cores, each having a raised or recessed structure configured to increase the creepage distance between the mating surfaces of the magnetic core and the winding support.

2. The high-voltage charging pile transformer as described in claim 1, characterized in that, The concave-convex structure is a stepped groove in the shape of a zigzag, specifically including a central extension and side extensions located on both sides of the central extension. The central extension is accommodated at one end of the first through cavity, and the side extensions are attached to the outer wall of the outer shell.

3. The high-voltage charging pile transformer as described in claim 1, characterized in that, A second gap region is formed between the first winding support portion and the second winding support portion, and the second gap region is filled with insulating material.

4. The high-voltage charging pile transformer as described in claim 3, characterized in that, The insulating material includes epoxy resin.

5. The high-voltage charging pile transformer as described in claim 4, characterized in that, The thickness of the first gap region is greater than or equal to 1.5 mm, and the thickness of the second gap region is 0.5-2 mm.

6. The high-voltage charging pile transformer as described in claim 1, characterized in that, The first winding support and the second winding support are made of flame-retardant polyethylene terephthalate.

7. The high-voltage charging pile transformer as described in claim 1, characterized in that, The thickness of the first winding support and the second winding support is 2-5mm.

8. The high-voltage charging pile transformer as described in claim 1, characterized in that, It also includes a retaining strap for securing the magnetic core assembly to the housing.

9. The high-voltage charging pile transformer as described in claim 8, characterized in that, It also includes a base, which is connected to one end of the fixing strap.

10. A high-voltage charging pile, characterized in that, It includes a high-voltage charging pile transformer as described in any one of claims 1-9.

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