Transformer magnetic powder core, transformer device and preparation method of transformer magnetic powder core

Abstract

The invention discloses a transformer magnetic powder core, a transformer device and a preparation method of the transformer magnetic powder core. The coating covers the surface of the magnetic powder core base body; the coating comprises a resin matrix and magnetic powder dispersed in the resin matrix, and the volume ratio of the magnetic powder in the coating is 3%-50%. The magnetic powder is added into the surface coating, so that the overall inductance value of the magnetic core is effectively improved, the increase of cost and copper loss caused by a method for increasing the inductance value by increasing the number of winding turns is avoided, and meanwhile, the coating also maintains good insulation and voltage-resistant performance and adhesion performance. Compared with a traditional scheme, the transformer magnetic powder core which is smaller in size, higher in inductance value and conversion efficiency and better in bias performance can be prepared.

Description

Technical Field

[0001] The present invention relates to electronic components, and in particular to a transformer magnetic powder core, a transformer component and a preparation method thereof. Background Art

[0002] A transformer is a static electrical device that operates based on the principle of electromagnetic induction. It is primarily used to change the voltage, current, and impedance of alternating current (AC), while simultaneously achieving circuit isolation and energy transmission. Its main components are a primary coil, a secondary coil, and an iron core (magnetic core). The transformer is connected to an AC power source through the primary coil, generating an alternating magnetic flux in the iron core, which in turn induces an electric potential in the secondary coil, achieving voltage conversion. The ratio of its input to output voltage is equal to the turns ratio of the coils.

[0003] Magnetic powder cores are composite soft magnetic materials formed by compacting ferromagnetic powder and an insulating dielectric through a specific process. The magnetic and electrical properties of magnetic powder cores are primarily determined by the powder material's properties and process control. These properties include the magnetic permeability, particle size distribution and morphology, and particle packing density of the magnetic particles. Process control includes the proportion of the insulating layer, pressure control during the compaction process, and heat treatment temperature and duration.

[0004] As the new energy vehicle and photovoltaic industries accelerate their iteration towards high power density and lightweight, the performance requirements for transformer components in core power conversion equipment have undergone a structural upgrade, and the demand for high performance and miniaturization is becoming increasingly urgent. The ferrite cores used in traditional transformers are limited by their inherent physical properties, such as low saturation magnetic induction intensity, insufficient DC bias tolerance, and large size, and can no longer meet the needs of emerging scenarios. In this context, assembled transformers (such as planar transformers and LLC resonant transformers) using new alloy magnetic powder core materials are becoming a breakthrough direction for the industry. However, the transformer alloy magnetic powder core has the problem of low magnetic permeability, which makes it difficult to achieve the required inductance value of the device. Increasing the number of winding turns to solve this problem will lead to a double increase in cost and copper loss. Therefore, there is an urgent need for a solution that can not only improve the inductance value of the transformer magnetic powder core, but also maintain or even improve the conversion efficiency of the transformer.

[0005] It should be noted that the information disclosed in the above background technology section is only used to understand the background of this application, and therefore may include information that does not constitute prior art known to ordinary technicians in this field. Summary of the Invention

[0006] The main purpose of the present invention is to overcome the defects existing in the above-mentioned background technology and provide a transformer magnetic powder core, a transformer device and a preparation method thereof.

[0007] To achieve the above object, the present invention adopts the following technical solutions:

[0008] A transformer magnetic powder core, comprising:

[0009] Magnetic powder core matrix;

[0010] A coating covering the surface of the magnetic powder core substrate;

[0011] The coating comprises a resin matrix and magnetic powder dispersed therein, and the volume proportion of the magnetic powder in the coating is 3% to 50%.

[0012] Furthermore, the thickness of the coating is 20 to 800 microns.

[0013] Furthermore, the magnetic powder is ferrite powder and / or alloy powder;

[0014] Furthermore, more than 50% of the ferrite powder has a particle size of less than 10 microns;

[0015] Furthermore, more than 50% of the alloy powder has a particle size greater than 3 microns.

[0016] Furthermore, the magnetic powder contains 30-98 wt% of Fe element, and also contains one or more of Zn, Ni, Co, Mn, Cu, Si, Al, and O elements.

[0017] Furthermore, the composition of the magnetic powder core matrix includes 80-87 wt% of Fe and 1-9 wt% of Si, and at least one element selected from the group consisting of Al, Cr, B, C, Nb, Mo, Co, Ni, V, P, and O;

[0018] The content of each element satisfies:

[0019] Al: 0.5~8wt%, Cr: 0.5~8wt%, B: 0.5~8wt%, C: 0.5~8wt%, Nb: 0.5~8wt%, Mo: 0. 5~8wt%, Co: 0.5~8wt%, Ni: 0.5~8wt%, V: 0.5~8wt%, P: 0.1~5wt%, O: 0.1~5wt%.

[0020] Furthermore, more than 50% of the powder particles of the magnetic powder core matrix have a particle size of 5 to 35 microns.

[0021] A transformer device comprises: at least one magnetic powder core and a coil wound on the magnetic powder core.

[0022] Furthermore, the transformer device includes a combination of multiple types of special-shaped magnetic powder cores, such as a combination of E-shaped and I-shaped magnetic powder cores.

[0023] A method for preparing the transformer magnetic powder core comprises:

[0024] preparing a magnetic powder core matrix;

[0025] Adding magnetic powder to the resin matrix to form a coating solution, wherein the magnetic powder accounts for 3% to 50% by volume;

[0026] Grinding and polishing the mating surfaces of the powder cores ensures that the combined powder cores fit well together;

[0027] The coating solution is evenly coated on the surface of the magnetic powder core matrix.

[0028] Furthermore, the coating is carried out using a spraying process, and the coating thickness is controlled to be 20 to 800 microns.

[0029] A method for preparing the transformer device, comprising:

[0030] preparing the transformer magnetic powder core;

[0031] Winding a coil on the magnetic powder core;

[0032] The magnetic powder core wound with the coil is assembled into a transformer device.

[0033] The present invention has the following beneficial effects:

[0034] The present invention proposes a transformer magnetic powder core, which adds ferrite powder and / or alloy magnetic powder to a traditional surface coating material used to meet the insulation and voltage resistance performance. By adding magnetic powder to the surface coating, the overall inductance of the magnetic core is effectively improved, while avoiding the cost and copper loss increase caused by the method of increasing the number of winding turns to increase the inductance.

[0035] The present invention can reduce the power loss of the magnetic core and improve the magnetic core bias performance while increasing the inductance of the transformer. At the same time, the coating can also maintain good insulation withstand voltage performance and adhesion performance.

[0036] When ferrite powder is added, the overall power loss of the core will be reduced due to the low power loss of ferrite, thereby improving the conversion efficiency of the device; when alloy powder is added, the overall Bs of the core can be improved.

[0037] The present invention can prepare a transformer magnetic powder core with smaller size, higher inductance value and conversion efficiency, and better bias performance.

[0038] Other beneficial effects of the embodiments of the present invention will be further described below. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 This is a front cross-sectional view of a transformer powder core and a transformer device according to an embodiment of the present invention.

[0040] Figure 2It is a side cross-sectional view of a transformer magnetic powder core and a transformer device according to an embodiment of the present invention.

[0041] Figure 3 This is a flow chart of a method for preparing a transformer magnetic powder core and a transformer device according to an embodiment of the present invention. DETAILED DESCRIPTION

[0042] The following is a detailed description of the embodiments of the present invention. It should be emphasized that the following description is only exemplary and is not intended to limit the scope of the present invention and its application.

[0043] It should be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it can be directly on the other element or indirectly on the other element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or indirectly connected to the other element. In addition, connection can be used for both fixing and coupling or communication.

[0044] It should be understood that the terms "length", "width", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing the embodiments of the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation, and therefore cannot be understood as limiting the present invention.

[0045] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be understood to indicate or imply relative importance or implicitly specify the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of such features. In the description of the embodiments of the present invention, "plurality" means two or more, unless otherwise specifically defined.

[0046] In order to ensure the insulation and voltage resistance performance of the alloy magnetic core, the surface of the magnetic core needs to be coated. The present invention proposes a transformer magnetic powder core, which adds ferrite powder and / or alloy magnetic powder to the traditional surface coating material used to meet the insulation and voltage resistance performance. By adding magnetic powder to the surface coating, the overall inductance of the magnetic core is effectively improved, and the cost and copper loss caused by increasing the number of winding turns to increase the inductance are avoided. At the same time, the coating also maintains good insulation and voltage resistance and adhesion performance.

[0047] See Figure 1 and Figure 2An embodiment of the present invention provides a transformer magnetic powder core, comprising: a magnetic powder core substrate 1; and a coating 2 covering the surface of the magnetic powder core substrate. The coating 2 comprises a resin matrix and magnetic powder dispersed therein, with the magnetic powder comprising 3% to 50% of the coating by volume.

[0048] In some embodiments, the coating 2 has a thickness of 20 to 800 microns.

[0049] In some embodiments, the magnetic powder is ferrite powder and / or alloy powder; when it is ferrite powder, more than 50% of the powder particles are less than 10 microns; when it is alloy powder, more than 50% of the powder particles are greater than 3 microns.

[0050] In some embodiments, the resin matrix of the coating 2 may include epoxy resin.

[0051] In some embodiments, the magnetic powder contains 30-98 wt % of Fe, and further contains one or more of Zn, Ni, Co, Mn, Cu, Si, Al, and O.

[0052] When ferrite powder is added to coating 2, the overall power loss of the core is reduced due to the low power loss of ferrite. This not only improves the overall inductance of the core, but also enhances the conversion efficiency of the device. When alloy powder is added to coating 2, the overall Bs of the core can be increased. The composition and content of the powder added to the coating can be adjusted to meet different performance requirements.

[0053] The magnetic powder core of the present invention utilizes an innovative coating design, which can reduce core power loss and improve core bias performance while increasing transformer inductance. At the same time, its coating can also maintain good insulation withstand voltage performance and adhesion performance.

[0054] In some embodiments, the composition of the magnetic powder core matrix 1 includes 80-87wt% Fe and 1-9wt% Si, as well as at least one element of the auxiliary chemical components Al, Cr, B, C, Nb, Mo, Co, Ni, V, P, and O.

[0055] As you can understand, the addition of Si (silicon) can improve the material's resistivity and reduce eddy current losses. Within a 1-9% Si content, Si can effectively suppress the formation of eddy currents, reducing the heating caused by them, thereby improving the efficiency of inductor devices. Auxiliary chemical composition can further adjust and optimize the material's electromagnetic properties. For example, elements such as Al and Cr can improve the material's hardness and corrosion resistance; elements such as B and C may contribute to the formation of amorphous materials, improving the material's density and uniformity; and elements such as Nb can inhibit grain growth, resulting in excellent nanocrystalline materials.

[0056] When the magnetic powder core component contains Al, the content of Al is 0.5 to 8 wt%; when the magnetic powder core component contains Cr, the content of Cr is 0.5 to 8 wt%; when the magnetic powder core component contains B, the content of B is 0.5 to 8 wt%; when the magnetic powder core component contains C, the content of C is 0.5 to 8 wt%; when the magnetic powder core component contains Nb, the content of Nb is 0.5 to 8 wt%; when the magnetic powder core component contains Mo, The content of Mo is 0.5-8wt%; when the magnetic powder core component contains Co, the content of Co is 0.5-8wt%; when the magnetic powder core component contains Ni, the content of Ni is 0.5-8wt%; when the magnetic powder core component contains V, the content of V is 0.5-8wt%; when the magnetic powder core component contains P, the content of P is 0.1-5wt%; when the magnetic powder core component contains O, the content of O is 0.1-5wt%.

[0057] In some embodiments, more than 50% of the powder particles of the magnetic powder core matrix 1 have a particle size of 5 to 35 microns.

[0058] like Figure 1 and Figure 2 As shown, an embodiment of the present invention further provides a transformer device, comprising: at least one magnetic powder core and a coil 3 wound on the magnetic powder core. The coil 3 may be an enameled copper wire.

[0059] Magnetic powder cores can be in various shapes, including E-type cores, I-type cores, P-type cores, U-type cores, toroidal cores, etc. Figure 1 As shown, in some embodiments, the transformer device includes a combination of E-type and I-type magnetic powder cores.

[0060] An embodiment of the present invention further provides a method for preparing the transformer magnetic powder core, comprising the following steps: preparing a magnetic powder core substrate 1; adding magnetic powder to a resin matrix used for preparing a surface coating to form a coating solution, wherein the magnetic powder accounts for 3% to 50% by volume; and uniformly applying the coating solution to the surface of the magnetic powder core substrate 1 to form a coating 2. Specific coating methods include, but are not limited to, spraying.

[0061] In some embodiments, the coating is performed using a spraying process, and the coating thickness is controlled to be 20 to 800 microns.

[0062] An embodiment of the present invention further provides a method for preparing the transformer device, comprising the following steps: preparing a transformer magnetic powder core using the aforementioned magnetic powder core preparation method; winding a coil 3 on the magnetic powder core; and assembling the magnetic powder core wound with the coil 3 into a transformer device.

[0063] like Figure 3 As shown, the specific process of the preparation method may include:

[0064] Preparation of magnetic powder core: Magnetic powder core is prepared by powder coating, granulation, pressing and sintering.

[0065] Grinding and polishing: Grinding and polishing are performed on the mating surfaces of the magnetic powder cores to make the combined magnetic powder cores fit better.

[0066] Preparation of coating: Add magnetic powder to the conventional coating with resin as the main body and disperse it evenly.

[0067] Spraying: Spraying a coating with magnetic powder on the surface of the magnetic powder core.

[0068] Winding: Winding enameled copper wire on magnetic powder core.

[0069] Assembly: Assemble the wound magnetic powder core.

[0070] The alloy metal / soft magnetic powder used to make the magnetic powder core can be composed of materials such as FeSiAl, FeSiBNbCu, and FeSiBPCu. The surface coating comprises a resin material, preferably epoxy resin, magnetic powder, and other additives. The magnetic powder can be ferrite powder or alloy powder, and its composition and amount can be adjusted based on the target performance.

[0071] The following further describes specific embodiments of the present invention and experimental verification.

[0072] Example 1

[0073] This embodiment provides a small transformer magnetic powder core and device. The transformer device comprises a magnetic powder core, a coil and a surface coating containing magnetic powder. The magnetic powder core is a FeSiAl soft magnetic composite material, in which the Fe mass fraction is 85%, the Si mass fraction is 9%, and the Al mass fraction is 6%. The two magnetic powder cores of the transformer are one E-type and the other I-type, and the particle size of the two magnetic powder cores is between 8 and 35 microns. Manganese zinc ferrite powder with a particle size of 1.2μm±0.2μm is added to a conventional coating solution, and the volume proportion of ferrite powder in the coating is 26%. After the magnetic powder core is ground and polished, the above-mentioned coating solution containing magnetic powder is sprayed on the surface of the magnetic core, and the coating thickness is 210 microns.

[0074] Comparative Example 1

[0075] This comparative example provides a transformer magnetic powder core and device. The transformer device comprises a magnetic powder core, a coil, and a conventional resin-based surface coating. The magnetic powder core is a FeSiAl soft magnetic composite material with a mass fraction of 85% Fe, 9% Si, and 6% Al. The transformer's two magnetic powder cores, one E-type and one I-type, have a particle size between 8 and 35 microns. After grinding and polishing, the core surface is sprayed with a conventional coating that does not contain magnetic powder.

[0076] The only difference between this comparative example 1 and example 1 is that the coating does not contain magnetic powder. Its size and processing technology are the same as those of example 1.

[0077] Experimental results:

[0078] The coated magnetic cores of Example 1 and Comparative Example 1 were tested separately. The transformer core prepared in Example 1 had an inductance of 110 μH (100 kHz) and a power loss of 62 mW / cm³ at room temperature, 50 kHz, and 100 mT. The core in Comparative Example 1 had an inductance of 95 μH (100 kHz) and a power loss of 85 mW / cm³ at room temperature, 50 kHz, and 100 mT. This demonstrates that Example 1 significantly outperforms Comparative Example 1 in both inductance and power loss, demonstrating the significant effect of adding magnetic powder to the coating on improving the performance of transformer powder cores.

[0079] Example 2

[0080] This embodiment provides a small transformer magnetic powder core and device. The transformer device comprises a magnetic powder core, a coil and a surface coating containing magnetic powder. The magnetic powder core is a FeSiBCuNb soft magnetic composite material. The two magnetic powder cores of the transformer are one E-type and one I-type, and the particle size of the two magnetic powder cores is between 8 and 30 microns. Iron-nickel powder is added to a conventional coating solution, with a specific composition of Fe55Ni45, a powder particle size between 5 and 20 microns, and an iron-nickel powder volume ratio of 19% in the coating. After the magnetic powder core is ground and polished, the above-mentioned coating solution containing magnetic powder is sprayed on the surface of the magnetic core, and the coating thickness is 300 microns.

[0081] Comparative Example 2

[0082] This comparative example provides a transformer magnetic powder core and device, wherein the transformer device comprises a magnetic powder core, a coil, and a surface coating containing magnetic powder. The magnetic powder core is a FeSiBCuNb soft magnetic composite material. The two magnetic powder cores of the transformer are one E-type and one I-type, and the particle size of the powder of the two magnetic powder cores is between 8 and 30 microns. Iron-nickel powder is added to a conventional coating solution, the specific composition is Fe55Ni45, the powder particle size is between 5 and 20 microns, and the volume proportion of the iron-nickel powder in the coating is 1%. After the magnetic powder core is ground and polished, the coating solution with a volume proportion of 1% of the above-mentioned iron-nickel is sprayed on the surface of the magnetic core.

[0083] The only difference between Comparative Example 2 and Example 2 is that the coating contains only 1% by volume of iron-nickel powder. The size and processing technology are the same as those of Example 2.

[0084] Experimental results:

[0085] The coated magnetic cores of Example 2 and Comparative Example 2 were tested separately. The transformer core prepared in Example 2 had an inductance of 105 μH (100 kHz) and a DC superposition performance of 52% (100 Oe). The inductance of the core in Comparative Example 2 was 89 μH (100 kHz) and a DC superposition performance of 47% (100 Oe). Because the amount of magnetic powder added in Comparative Example 2 was very small, the effect on performance was minimal. It can be seen that Example 2 significantly outperformed Comparative Example 2 in both inductance and DC superposition performance, demonstrating the significant effect of adding an appropriate proportion of magnetic powder to the coating on improving the performance of transformer magnetic powder cores.

[0086] Example 3

[0087] This embodiment provides a small transformer magnetic powder core and device. The transformer device comprises a magnetic powder core, a coil, and a surface coating containing magnetic powder. The magnetic powder core is a FeSiAl soft magnetic composite material, in which the mass fraction of Fe is 85%, the mass fraction of Si is 9.6%, and the mass fraction of Al is 5.4%. The two magnetic powder cores of the transformer are one E-type and one I-type, and the particle size of the powder of the two magnetic powder cores is between 5 and 35 microns. Iron-nickel powder and manganese-zinc ferrite powder are added to a conventional coating solution. The specific composition of iron-nickel is Fe55Ni45, the powder particle size is between 6 and 25 microns, and the particle size of the ferrite powder is 1.3μm±0.2μm. The volume proportion of the iron-nickel and ferrite powder particles in the coating is 22%. After the magnetic powder core is ground and polished, the above-mentioned coating solution containing magnetic powder is sprayed on the surface of the magnetic core. The coating thickness is 260 microns.

[0088] Comparative Example 3

[0089] This comparative example provides a transformer magnetic powder core and device, wherein the transformer device comprises a magnetic powder core, a coil, and a conventional surface coating mainly composed of resin. The magnetic powder core is a FeSiAl soft magnetic composite material, wherein the Fe mass fraction, the Si mass fraction, and the Al mass fraction are 85%, 9.6%, and 5.4%, respectively. The two magnetic powder cores of the transformer are one E-type and one I-type, and the particle size of the powder of the two magnetic powder cores is between 5 and 35 microns. After the magnetic powder core is ground and polished, a conventional coating that does not contain magnetic powder is sprayed on the surface of the magnetic core. The only difference between this comparative example 3 and Example 3 is that the coating does not contain magnetic powder. Its size and processing technology are the same as those of Example 3.

[0090] Comparative Example 4

[0091] This comparative example provides a transformer magnetic powder core and device, wherein the transformer device comprises a magnetic powder core, a coil, and a surface coating containing magnetic powder. The magnetic powder core is a FeSiAl soft magnetic composite material, wherein the Fe mass fraction, the Si mass fraction, and the Al mass fraction are 85%, 9.6%, and 5.4%, respectively. One of the two magnetic powder cores of the transformer is E-type and the other is I-type, and the particle size of the two magnetic powder core powders is between 5 and 35 microns. Iron-nickel powder and manganese-zinc ferrite powder are added to a conventional coating solution, wherein the specific composition of iron-nickel is Fe55Ni45, the powder particle size is between 6 and 25 microns, the ferrite powder particle size is 1.3μm±0.2μm, and the volume proportion of iron-nickel and ferrite powder particles in the coating is 58%. After the magnetic powder core is ground and polished, the coating solution containing 58% of the magnetic powder by volume is sprayed on the surface of the magnetic core.

[0092] The only difference between Comparative Example 4 and Example 3 is that the coating contains 58% by volume of magnetic powder. The dimensions and processing technology are the same as those of Example 3.

[0093] Experimental results:

[0094] The magnetic cores containing coatings in Example 3, Comparative Example 3, and Comparative Example 4 were tested. The transformer core prepared in Example 3 had an inductance of 107 μH (100 kHz), a DC superposition performance of 59% (100 Oe), and a core power loss of 71 mW / cm3 at room temperature and 50 kHz / 100 mT. The core inductance in Comparative Example 3 was 94 μH (100 kHz), a DC superposition performance of 53% (100 Oe), and a core power loss of 86 mW / cm3 at room temperature and 50 kHz / 100 mT. The coating prepared in Comparative Example 4 had poor adhesion and was easily detached, resulting in substandard insulation and withstand voltage performance. Example 3 outperformed Comparative Example 3, which did not contain magnetic powder in the coating, in terms of inductance, DC superposition performance, and power loss. However, due to the excessive amount of magnetic powder added, Comparative Example 4 had poor adhesion and was easily detached, resulting in substandard insulation and withstand voltage performance. The present invention can take into account both the core performance and the coating reliability by adding magnetic powder to the coating and controlling the addition amount within the range of 3% to 50%.

[0095] Example 4

[0096] This embodiment provides a small transformer magnetic powder core and device, wherein the transformer device comprises a magnetic powder core, a coil, and a surface coating containing magnetic powder. The magnetic powder core is a FeSiAl soft magnetic composite material, wherein the Fe mass fraction of the soft magnetic composite material is 85.5%, the Si mass fraction is 9.1%, and the Al mass fraction is 5.4%. Both magnetic powder cores of the transformer are E-type, and the particle size of the powder of the two magnetic powder cores is between 5 and 40 microns. Nickel-zinc ferrite powder is added to a conventional coating solution, wherein the particle size of the nickel-zinc ferrite powder is less than 5 microns, and the volume proportion of the ferrite powder in the coating is 18%. After the magnetic powder core is ground and polished, the above-mentioned coating solution containing magnetic powder is sprayed on the surface of the magnetic core, and the coating thickness is 240 microns.

[0097] Comparative Example 5

[0098] This comparative example provides a transformer magnetic powder core and device. The transformer device comprises a magnetic powder core, a coil, and a conventional resin-based surface coating. The magnetic powder core is a FeSiAl soft magnetic composite material with a mass fraction of 85.5% Fe, 9.1% Si, and 5.4% Al. Both transformer magnetic powder cores are E-shaped, with a particle size of 5 to 40 microns. After grinding and polishing, the magnetic powder cores are sprayed with a conventional coating that does not contain magnetic powder.

[0099] The only difference between this comparative example 5 and example 4 is that the coating does not contain magnetic powder. Its size and processing technology are the same as those of example 4.

[0100] Experimental results:

[0101] Testing of the coated magnetic cores from Example 4 and Comparative Example 5 revealed that the transformer core prepared in Example 4 had an inductance of 129 μH (100 kHz) and a power loss of 75 mW / cm³ at room temperature and 50 kHz / 100 mT. The core in Comparative Example 1 had an inductance of 116 μH (100 kHz) and a power loss of 92 mW / cm³ at room temperature and 50 kHz / 100 mT. This demonstrates the beneficial effect of adding magnetic powder to the coating on the electrical performance of transformer cores.

[0102] In summary, the present invention provides a transformer magnetic powder core, a transformer device and a preparation method thereof. In the present invention, ferrite powder and / or alloy magnetic powder with a volume ratio of 3% to 50% is added to the traditional coating material for meeting the insulation and voltage resistance performance. By adding the magnetic powder to the surface coating, the overall inductance of the magnetic core is effectively improved, and the cost and copper loss caused by the method of increasing the number of winding turns to increase the inductance are avoided. While increasing the inductance of the transformer, the present invention can reduce the power loss of the magnetic core and improve the bias performance of the magnetic core. At the same time, the coating can maintain good insulation and voltage resistance and adhesion performance. By designing the surface coating solution, the present invention can prepare a transformer magnetic powder core with smaller size, higher inductance and conversion efficiency, and better bias performance.

[0103] The above description further details the present invention in conjunction with specific / preferred embodiments, and the specific implementation of the present invention should not be construed as being limited to these descriptions. Persons skilled in the art will appreciate that, without departing from the spirit of the present invention, they may make various substitutions or modifications to the described embodiments, and these substitutions or modifications should be considered to fall within the scope of protection of the present invention. Throughout this specification, reference to terms such as "one embodiment," "some embodiments," "preferred embodiments," "examples," "specific examples," or "some examples" indicates that the specific features, structures, materials, or characteristics described in conjunction with such embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of these terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Persons skilled in the art may combine and assemble the different embodiments or examples described in this specification, as well as features of different embodiments or examples, without conflicting opinions. Although the embodiments of the present invention and their advantages have been described in detail, it should be understood that various changes, substitutions, and modifications may be made herein without departing from the scope of protection of the patent application.

Claims

1. A transformer magnetic powder core, characterized in that: include: Magnetic powder core matrix; A coating covering the surface of the magnetic powder core substrate; The coating comprises a resin matrix and magnetic powder dispersed therein, and the volume proportion of the magnetic powder in the coating is 3% to 50%.

2. The transformer powder core according to claim 1, wherein: The thickness of the coating is 20 to 800 microns.

3. The transformer magnetic powder core according to claim 1 or 2, characterized in that: The magnetic powder is ferrite powder and / or alloy powder.

4. The transformer magnetic powder core according to claim 3, wherein: More than 50% of the ferrite powder has a particle size smaller than 10 microns; and more than 50% of the alloy powder has a particle size larger than 3 microns.

5. The transformer magnetic powder core according to claim 3 or 4, characterized in that: The magnetic powder contains 30-98 wt% of Fe element and further contains one or more of Zn, Ni, Co, Mn, Cu, Si, Al, and O elements.

6. The transformer magnetic powder core according to any one of claims 1 to 5, characterized in that: The composition of the magnetic powder core matrix includes 80-87 wt% of Fe and 1-9 wt% of Si, and at least one element selected from the group consisting of Al, Cr, B, C, Nb, Mo, Co, Ni, V, P, and O; The content of each element satisfies: Al: 0.5~8wt%, Cr: 0.5~8wt%, B: 0.5~8wt%, C: 0.5~8wt%, Nb: 0.5~8wt%, Mo:

0. 5~8wt%, Co: 0.5~8wt%, Ni: 0.5~8wt%, V: 0.5~8wt%, P: 0.1~5wt%, O: 0.1~5wt%.

7. The transformer powder core according to claim 6, wherein: More than 50% of the powder particles in the magnetic powder core matrix have a particle size of 5 to 35 microns.

8. A transformer device, characterized in that: include: At least one magnetic powder core according to any one of claims 1 to 7; A coil is wound around the magnetic powder core.

9. A method for preparing a transformer magnetic powder core according to any one of claims 1 to 7, characterized in that: include: preparing a magnetic powder core matrix; Adding magnetic powder to the resin matrix to form a coating solution, wherein the magnetic powder accounts for 3% to 50% by volume; The coating solution is evenly coated on the surface of the magnetic powder core matrix.

10. A method for preparing a transformer device according to claim 8, characterized in that: include: Prepare a magnetic powder core by the method according to claim 9; Winding a coil on the magnetic powder core; The magnetic powder core wound with the coil is assembled into a transformer device.

Images