Nanocrystalline triangular core of high-frequency transformer with interlayer insulation superposition structure

Abstract

The utility model discloses a kind of nanocrystalline triangular core of middle-high frequency transformer with interlayer insulation superposition structure, nanocrystalline triangular core includes a plurality of nanocrystalline triangular core subunits of laminated arrangement and ground wire, and nanocrystalline triangular core subunit is wound from iron-based nanocrystalline alloy strip material;The outside of nanocrystalline triangular core subunit is equipped with acetal drying glue liquid solidification layer;Two nanocrystalline triangular core subunits between adjacent are equipped with grid cloth insulation cushion, and first cementing layer is arranged between nanocrystalline triangular core subunit and grid cloth insulation cushion, and first cementing layer is epoxy resin glue;In laminated direction, the outside of nanocrystalline triangular core subunit at both ends is equipped with second cementing layer, buffer insulation layer, third cementing layer and encapsulation layer in sequence;Second cementing layer is epoxy resin glue, and buffer insulation layer is heat-conducting silica gel pad. It avoids the hard contact of brittle core and external encapsulation layer, reduces the risk of core rupture caused by stress concentration.

Description

Technical Field

[0001] This utility model relates to the field of transformer core technology, and in particular to a nanocrystalline triangular core for medium and high frequency transformers with an interlayer insulation superposition structure. Background Technology

[0002] As power electronics technology continues to develop towards higher frequencies, smaller sizes, and higher efficiency, the performance of medium- and high-frequency transformers, as core energy conversion components, directly determines the size, efficiency, and reliability of the entire power supply system. Nanocrystalline soft magnetic materials, due to their superior characteristics such as high saturation magnetic induction, high permeability, and low loss, especially in the medium- and high-frequency range of 10kHz to hundreds of kHz, exhibit performance far superior to traditional ferrite materials, making them an ideal choice for manufacturing high-end medium- and high-frequency transformer cores.

[0003] To adapt to specific installation spaces and optimize magnetic circuits, triangular core structures have emerged. In existing technologies, such as the scheme disclosed in Chinese Patent Publication No. CN115497715A, a structure is adopted that combines two independent nanocrystalline triangular core sub-body structures by stacking. This scheme prepares individual core sub-body structures through processes such as winding, annealing, and curing. Then, two sub-body structures are bonded together using mesh insulating pads and epoxy resin adhesive, and finally encapsulated with epoxy glass cloth sheets on both top and bottom.

[0004] However, the above-mentioned existing technical solutions still have the following technical problems:

[0005] First, the poor mechanical stress matching poses a risk of hidden damage to the core. Nanocrystalline materials exhibit magnetostriction under alternating magnetic fields, inducing micro-vibrations. Current structures only use a mesh insulating pad between the core and the external rigid epoxy glass cloth plate, bonded with rigid epoxy resin. This "hard-on-hard" connection method is insufficient to effectively absorb and buffer continuous micro-vibration energy, causing stress concentration on the brittle nanocrystalline core. Over long-term operation, this easily leads to the generation and propagation of micro-cracks, directly affecting the core's magnetic properties and long-term service life.

[0006] Secondly, insufficient heat dissipation efficiency limits the improvement of power density. In medium and high frequency applications, core losses are dissipated as heat. Both the mesh fabric and epoxy glass cloth are poor conductors of heat, making it difficult to quickly dissipate the heat generated by the core during operation, resulting in a higher internal temperature rise. This not only exacerbates the degradation of magnetic properties but also limits further increases in transformer power density.

[0007] Finally, the overall structure's reliability under harsh operating conditions needs improvement. Epoxy glass cloth (FR-4) has limitations in impact resistance and long-term heat aging resistance; the integrity of the encapsulation structure may be affected under harsh environments such as vibration and thermal shock.

[0008] Therefore, there is an urgent need in this field for a new type of transformer core structure that can fundamentally improve mechanical stress adaptation, enhance heat dissipation, and improve overall structural reliability while inheriting the excellent electromagnetic properties and low loss at medium and high frequencies of nanocrystalline materials. Utility Model Content

[0009] In view of this, the present invention proposes a nanocrystalline triangular iron core for a medium- and high-frequency transformer with an interlayer insulation superposition structure, with the aim of solving at least one of the above-mentioned technical problems.

[0010] The solution provided by this utility model includes:

[0011] A nanocrystalline triangular iron core for a medium- and high-frequency transformer with an interlayer insulation superposition structure, the nanocrystalline triangular iron core comprising multiple stacked nanocrystalline triangular iron core sub-body and a grounding wire, wherein the nanocrystalline triangular iron core sub-body is wound from iron-based nanocrystalline alloy strip;

[0012] The exterior of the nanocrystalline triangular iron core is provided with an acetal drying adhesive curing layer;

[0013] A mesh cloth insulating pad is provided between two adjacent nanocrystalline triangular iron core bodies, and a first adhesive layer is provided between the nanocrystalline triangular iron core body and the mesh cloth insulating pad, the first adhesive layer being epoxy resin adhesive;

[0014] In the stacking direction, a second adhesive layer, a buffer insulation layer, a third adhesive layer, and an encapsulation layer are sequentially provided on the outer side of the nanocrystalline triangular iron core at both ends; wherein, the second adhesive layer is epoxy resin adhesive, and the buffer insulation layer is a thermally conductive silicone pad.

[0015] As a further optional solution, the third adhesive layer is a modified polyurethane thermally conductive structural adhesive or an organosilicon thermally conductive adhesive.

[0016] As a further alternative, the encapsulation layer is a bulk molding compound.

[0017] As a further optional solution, the nanocrystalline triangular iron core consists of two parts.

[0018] Compared with the prior art, this application has at least the following advantages:

[0019] This application sequentially comprises a second adhesive layer, a buffer insulation layer, a third adhesive layer, and an encapsulation layer on the outer sides of the nanocrystalline triangular iron core at both ends. The crucial buffer insulation layer is a thermally conductive silicone pad. This design creates a "rigid-flexible-rigid" gradient transition from the iron core to the external encapsulation: the second adhesive layer (epoxy resin adhesive) provides initial strong bonding, while the thermally conductive silicone pad, utilizing its excellent elasticity, effectively absorbs and buffers the microscopic vibrations and stresses generated by the magnetostriction of the nanocrystalline iron core, avoiding direct hard contact between the brittle iron core and the external encapsulation layer, and reducing the risk of core breakage due to stress concentration. Simultaneously, the thermally conductive silicone pad acts as a heat conduction channel, rapidly dissipating the heat generated during iron core operation, synergistically improving overall heat dissipation efficiency, thereby jointly ensuring the stability and lifespan of the iron core during long-term operation.

[0020] By incorporating an encapsulation layer and ensuring reliable bonding with the internal core components, a robust protective shell is provided for the entire core assembly. This structure enhances the core's resistance to external mechanical stress and vibration. Simultaneously, the mesh insulation pads located between the core sub-body sections and the outer buffer insulation layer (thermally conductive silicone pad) together form a complete internal and external insulation system, ensuring the required electrical insulation strength. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the structure of a nanocrystalline triangular iron core of a medium- and high-frequency transformer with an interlayer insulation superposition structure in one embodiment;

[0022] Figure 2 This is a schematic cross-sectional view of a nanocrystalline triangular iron core of a medium- and high-frequency transformer with an interlayer insulation superposition structure in one embodiment.

[0023] In the diagram: 1. Nanocrystalline triangular iron core; 2. Grounding wire; 3. Acetal drying adhesive curing layer; 4. Mesh cloth insulation pad layer; 5. First adhesive layer; 6. Second adhesive layer; 7. Buffer insulation layer; 8. Third adhesive layer; 9. Encapsulation layer. Detailed Implementation

[0024] The following embodiments are used to illustrate the present invention, but are not intended to limit the scope of the present invention.

[0025] In the description of this utility model, it should be understood that the terms "upper", "lower", "front", "rear", "vertical", "horizontal", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model.

[0026] In this utility model, unless otherwise explicitly specified and limited, the terms "installation," "connection," "joining," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.

[0027] In this utility model, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact through an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0028] The specific embodiments of this utility model will be described in further detail below with reference to the accompanying drawings and examples.

[0029] refer to Figure 1 and Figure 2 An embodiment of this utility model shows a nanocrystalline triangular iron core for a medium- and high-frequency transformer with an interlayer insulation superposition structure. The nanocrystalline triangular iron core includes multiple stacked nanocrystalline triangular iron core sub-body 1 and a grounding wire 2. The nanocrystalline triangular iron core sub-body 1 is wound from iron-based nanocrystalline alloy strip.

[0030] The exterior of the nanocrystalline triangular iron core 1 is provided with an acetal drying adhesive curing layer 3;

[0031] A mesh cloth insulating pad 4 is provided between two adjacent nanocrystalline triangular iron core bodies 1, and a first adhesive layer 5 is provided between the nanocrystalline triangular iron core body 1 and the mesh cloth insulating pad 4. The first adhesive layer 5 is epoxy resin adhesive.

[0032] In the stacking direction, a second adhesive layer 6, a buffer insulation layer 7, a third adhesive layer 8, and an encapsulation layer 9 are sequentially provided on the outer side of the nanocrystalline triangular iron core body 1 located at both ends; wherein, the second adhesive layer 6 is epoxy resin adhesive, and the buffer insulation layer 7 is a thermally conductive silicone pad.

[0033] Specifically, each nanocrystalline triangular iron core 1 has an acetal drying adhesive curing layer 3 on its exterior. This acetal drying adhesive curing layer 3 is formed by applying acetal drying adhesive and drying curing after the nanocrystalline triangular iron core 1 is wound and formed. Its function is to solidify the brittle nanocrystalline strip into a structurally stable whole.

[0034] A mesh fabric insulating pad 4 is disposed between two adjacent nanocrystalline triangular iron core bodies 1. This mesh structure ensures insulation performance while providing space for adhesive penetration. The nanocrystalline triangular iron core bodies 1 and the mesh fabric insulating pad 4 are firmly bonded together by a first adhesive layer 5, which is made of epoxy resin, ensuring reliable connection between the nanocrystalline triangular iron core bodies 1 and overall structural stability.

[0035] In the stacking direction, the outer sides of the nanocrystalline triangular iron core sub-body 1 at both ends adopt a multi-layer composite structure design, which includes a second bonding layer 6, a buffer insulation layer 7, a third bonding layer 8, and an encapsulation layer 9 in sequence. The second bonding layer 6 also uses epoxy resin to achieve the initial bonding between the nanocrystalline triangular iron core sub-body 1 and the buffer insulation layer 7; the buffer insulation layer 7 uses a thermally conductive silicone pad, which provides excellent elastic cushioning performance and can effectively conduct heat; the third bonding layer 8 is used to connect the buffer layer and the outer encapsulation layer 9; the outermost encapsulation layer 9 provides the final mechanical protection and insulation guarantee for the entire iron core assembly.

[0036] In this embodiment, a thermally conductive silicone pad is used as the buffer insulation layer 7, which effectively solves the stress concentration problem caused by magnetostriction of nanocrystalline materials and significantly improves the heat dissipation performance of the iron core. Reliable connections are achieved between the layers through different adhesive layers, ensuring both the integrity of the structure and providing excellent stress buffering and thermal management functions, resulting in higher reliability and a longer service life for the iron core under medium- and high-frequency operating conditions.

[0037] In some embodiments, the third adhesive layer 8 is a modified polyurethane thermally conductive structural adhesive.

[0038] The modified polyurethane thermally conductive structural adhesive, after curing, forms a tough elastomer. Its unique microstructure allows it to effectively absorb and release stress through its minute deformation when subjected to mechanical vibration and thermal expansion and contraction. This property makes it an ideal bridge connecting the flexible buffer insulation layer 7 (thermal conductive silicone pad) and the rigid encapsulation layer 9. It avoids the stress concentration problems that may be caused by the rigid adhesive layer, thereby further improving the gradient stress buffer structure from the core to the outer shell. At the same time, its thermal conductivity ensures that heat can be smoothly transferred from the thermal conductive silicone pad to the encapsulation layer 9, maintaining the continuity of the overall heat dissipation path.

[0039] In other embodiments, the third adhesive layer 8 may also be made of silicone thermally conductive adhesive. Silicone materials are known for their excellent temperature resistance, aging resistance, and stable chemical properties. Silicone thermally conductive adhesives retain permanent flexibility after curing, maintaining elasticity over a wide temperature range for extended periods, providing durable and reliable stress buffering for the entire laminated structure. Their excellent insulation and thermal conductivity also ensure both electrical safety and efficient heat dissipation.

[0040] Regardless of whether the third adhesive layer 8 is made of modified polyurethane thermally conductive structural adhesive or silicone thermally conductive adhesive, its core beneficial effect is that by introducing the third adhesive layer 8, which has flexibility and thermal conductivity, not only is a firm bond between the buffer insulation layer 7 and the encapsulation layer 9 achieved, but more importantly, as a flexible stress dissipation interface and an effective heat conduction link, it works synergistically with the buffer insulation layer 7 (thermal conductive silicone pad) to jointly improve the core's ability to resist mechanical stress and high-temperature impact, and significantly enhance the long-term reliability of the product under harsh working conditions.

[0041] In some embodiments, the encapsulation layer 9 is a bulk molding compound.

[0042] Bulk molding compound is a prepreg material composed of unsaturated polyester resin, thickener, filler materials (such as calcium carbonate and talc), and chopped glass fibers. In the manufacturing process, the proportioned bulk molding compound is placed into a preheated mold, and it is heated and pressurized to flow and fill the mold cavity. After cross-linking and curing, it forms an encapsulation shell that perfectly fits the shape of the iron core assembly.

[0043] In this embodiment, a bulk molding compound is selected as the encapsulation layer 9. Firstly, after curing, it possesses extremely high mechanical strength, rigidity, and impact resistance. Compared to traditional epoxy glass cloth boards, it provides more robust protection for the brittle nanocrystalline iron core, greatly enhancing the nanocrystalline triangular iron core's ability to resist external mechanical stress and vibration during transportation, installation, and operation. Secondly, the bulk molding compound itself possesses excellent electrical insulation properties, arc resistance, and tracking resistance, ensuring the long-term insulation reliability of the product. Furthermore, this material exhibits good heat resistance and thermal stability; its heat distortion temperature is far higher than the transformer's conventional operating temperature, ensuring the dimensional stability and performance maintenance of the encapsulation structure under high-temperature environments.

[0044] In this embodiment, two nanocrystalline triangular iron core bodies 1 are used. In other embodiments, more nanocrystalline triangular iron core bodies 1 may be used as needed.

[0045] In summary, this application provides a nanocrystalline triangular core for a medium- and high-frequency transformer with an interlayer insulation superposition structure. On the outer sides of the nanocrystalline triangular core sub-body 1 located at both ends, a second bonding layer 6, a buffer insulation layer 7, a third bonding layer 8, and an encapsulation layer 9 are sequentially disposed. The crucial buffer insulation layer 7 is a thermally conductive silicone pad. This design creates a "rigid-flexible-rigid" gradient transition from the core to the external encapsulation: the second bonding layer 6 (epoxy resin adhesive) provides initial strong adhesion, while the thermally conductive silicone pad, utilizing its excellent elasticity, effectively absorbs and buffers the micro-vibrations and stresses generated by magnetostriction of the nanocrystalline core, avoiding direct hard contact between the brittle core and the external encapsulation layer 9, and reducing the risk of core breakage due to stress concentration. Simultaneously, the thermally conductive silicone pad, as a heat conduction channel, can quickly dissipate the heat generated during core operation, synergistically improving the overall heat dissipation efficiency, thereby jointly ensuring the stability and lifespan of the core during long-term operation.

[0046] In the above embodiments, the descriptions of each embodiment have different focuses. For parts not described in detail in a certain embodiment, please refer to the relevant descriptions of other embodiments.

[0047] The above description is only a preferred embodiment of the present utility model. It should be noted that for those skilled in the art, several improvements and substitutions can be made without departing from the technical principles of the present utility model, and these improvements and substitutions should also be considered within the protection scope of the present utility model.

Claims

1. A nanocrystalline triangular core for a medium- and high-frequency transformer with an interlayer insulation superposition structure, wherein the nanocrystalline triangular core comprises multiple stacked nanocrystalline triangular core sub-body pieces and a grounding wire, and the nanocrystalline triangular core sub-body pieces are wound from iron-based nanocrystalline alloy strip; characterized in that: The exterior of the nanocrystalline triangular iron core is provided with an acetal drying adhesive curing layer; A mesh cloth insulating pad is provided between two adjacent nanocrystalline triangular iron core bodies, and a first adhesive layer is provided between the nanocrystalline triangular iron core body and the mesh cloth insulating pad, the first adhesive layer being epoxy resin adhesive; In the stacking direction, a second adhesive layer, a buffer insulation layer, a third adhesive layer, and an encapsulation layer are sequentially provided on the outer side of the nanocrystalline triangular iron core at both ends; wherein, the second adhesive layer is epoxy resin adhesive, and the buffer insulation layer is a thermally conductive silicone pad.

2. The nanocrystalline triangular core of a medium-to-high frequency transformer with an interlayer insulation superposition structure according to claim 1, characterized in that: The third adhesive layer is a modified polyurethane thermally conductive structural adhesive or an organosilicon thermally conductive adhesive.

3. The nanocrystalline triangular core of a medium-to-high frequency transformer with an interlayer insulation superposition structure according to claim 1, characterized in that: The encapsulation layer is a bulk molding compound.

4. The nanocrystalline triangular core of a medium-to-high frequency transformer with an interlayer insulation superposition structure according to claim 1, characterized in that: The nanocrystalline triangular iron core consists of two parts.

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