3D inductor based on ampere's law and method thereof

Abstract

This invention relates to the field of power electronic component manufacturing and advanced composite material application technology, specifically a 3D inductor based on Ampere's law and its method; it includes a functional composite skeleton, a 3D precision interlocking winding, and a magnetic core assembly; the system uses a thermally conductive insulating matrix and soft magnetic powder composite molded skeleton, and physically fills the air gap between winding layers through stepped positioning ribs; its core is to utilize the high thermal conductivity of the skeleton to establish a low thermal resistance heat dissipation path, changing the heat conduction mode from coil to air to coil directly to the skeleton; this invention effectively reduces the temperature gradient difference between the core temperature and the surface temperature inside the coil through an embedded heat dissipation array, solving the heat dissipation problem under high power density and significantly improving device performance.

Description

Technical Field

[0001] This invention relates to the field of power electronic component manufacturing and advanced composite material application technology, specifically to a 3D inductor based on Ampere's law and its method. Background Technology

[0002] In high-power power electronics applications, inductors, as core magnetic components, are widely used in automotive electronics and industrial control systems. They need to maintain stable electromagnetic performance and thermal safety under high-frequency and high-current conditions. Existing inductor manufacturing solutions generally use insulated plastic frames combined with layered winding processes. Air gaps inevitably exist between coil turns and layers. These air gaps form discontinuous interfaces with high thermal resistance at the microscopic level, blocking the effective heat conduction path. Due to the extremely low thermal conductivity of air and traditional frame materials such as bakelite, the Joule heat generated inside the coil is difficult to be effectively conducted to the outside radially, resulting in a significantly higher temperature at the center of the device than at the surface, thus forming a severe thermal island effect. At the same time, when dealing with high-current impacts, the inductance often drops sharply due to the rapid nonlinear increase in the magnetic reluctance of the main magnetic circuit, lacking the soft saturation characteristics that can ensure circuit stability. In addition, in high-vibration environments such as automotive applications, traditional winding structures that rely solely on friction or adhesive bonding lack rigid mechanical constraints, making them prone to relative coil displacement, which can lead to mechanical noise or structural failure.

[0003] Therefore, how to construct an inductor architecture that can simultaneously achieve low thermal resistance heat dissipation path, high current soft saturation control, and high mechanical stability by optimizing the skeleton material properties and topology has become an urgent technical problem to be solved. Summary of the Invention

[0004] In view of the shortcomings of the prior art, the purpose of this invention is to provide a 3D inductor and method based on Ampere's law, which can solve the technical problems existing in the prior art. Specifically, the technical solution of this invention is as follows:

[0005] A method for manufacturing 3D inductors based on Ampere's law, comprising:

[0006] S1. A functional composite skeleton and a 3D precision interlocking winding are set at the geometric center of the magnetic core assembly; the functional composite skeleton includes a central shaft column and multiple stepped positioning ribs that extend radially outward and have axial limiting slots on the sides.

[0007] S2. The functional composite skeleton is formed by mixing a thermally conductive and insulating matrix with soft magnetic powder to give it semi-magnetic and thermally conductive characteristics.

[0008] S3. Flat copper wires are sequentially inserted into the limiting slots as 3D precision interlocking windings, and the air gap between winding layers is filled by stepped positioning ribs.

[0009] S4. Assemble the components by inserting the stepped positioning ribs deep into the 3D precision interlocking winding to establish a low thermal resistance output path, and wrap the magnetic core assembly around the functional composite skeleton and the 3D precision interlocking winding to establish a closed main magnetic circuit.

[0010] S5. Package and post-process the assembled device to form a finished inductor with anisotropic magnetic-thermal characteristics.

[0011] Preferably, step S1 includes the following steps prior to:

[0012] S1.1 constructs a magneto-thermal physical model with the optimization goals of improving soft saturation characteristics under high current and reducing the core temperature inside the coil. It simulates and calculates the permeability parameters of the functional composite skeleton and the geometric topological parameters of the stepped positioning ribs.

[0013] Preferably, the ends of the stepped positioning ribs are provided with L-shaped buckle structures. In step S1.1, the optimization objectives also include the coil displacement under mechanical vibration, and the geometric topology parameters include the depth of the limiting slot and the size of the L-shaped buckle structure.

[0014] Preferably, step S3 includes:

[0015] Start the winding equipment and guide the flat copper wire to the limit slot;

[0016] Tension is applied to embed the flat copper wire into the limiting slot, and stepped positioning ribs are used to limit the axial displacement of the flat copper wire.

[0017] Mechanical locking is achieved by using the end structure of stepped positioning ribs to restrict the radial displacement of the 3D precision interlocking winding.

[0018] Preferably, in step S1, the material of the magnetic core assembly is high-frequency low-loss ferrite, and the permeability of the functional composite skeleton is lower than that of the magnetic core assembly but higher than that of air.

[0019] Preferably, in step S2, the composite material is formulated from 60% to 80% by mass of aluminum nitride powder, 10% to 20% by mass of iron-silicon-aluminum magnetic powder, and a binder, wherein the aluminum nitride powder has a particle size of 10-50 μm. .

[0020] Preferably, the functional composite skeleton is formed by high-pressure injection molding or powder metallurgy, and the thermal conductivity of the functional composite skeleton is greater than that of the other two. .

[0021] Preferably, step S5 includes:

[0022] Vacuum encapsulation of the entire device;

[0023] The surface of the device is coated with carbon nanotubes or oxidized and blackened to make the infrared emissivity of the device surface greater than 0.9.

[0024] A 3D inductor based on Ampere's law includes:

[0025] A functional composite framework is positioned at the geometric center of the 3D inductor;

[0026] 3D precision interlocking windings are physically fitted onto the outside of the functional composite frame;

[0027] The magnetic core assembly is encased and disposed around the 3D precision interlocking winding and the functional composite skeleton. The functional composite skeleton is a semi-magnetic solid containing a thermally conductive insulating matrix and soft magnetic powder. The functional composite skeleton is provided with stepped positioning ribs that are inserted into the gaps of the 3D precision interlocking winding.

[0028] Preferably, the bottom of the functional composite skeleton is provided with metallized pads or thermally conductive bosses, which are thermally connected to the stepped positioning ribs, and the pins of the 3D precision interlocking winding are connected to the metallized pads.

[0029] Compared with the prior art, the present invention has the following improvements and advantages:

[0030] 1. This invention fundamentally alters the thermodynamic behavior of devices by utilizing the high thermal conductivity of a functional composite skeleton. The stepped positioning ribs, acting as a solid thermal conductive medium, physically fill the interlayer air gaps originally present in the 3D precision interlocking winding. This structural improvement transforms the heat conduction path from the traditional coil-to-air-to-insulation layer to a direct coil-to-functional composite skeleton. Because the thermal conductivity of the functional composite skeleton is significantly higher than that of air and ordinary insulating plastic, the heat generated deep within the coil can be rapidly conducted outwards along the low thermal resistance stepped positioning ribs to the bottom metallized pads or thermally conductive bosses. This embedded heat dissipation array effectively reduces the temperature gradient between the core and surface of the coil, improving the power density limit of the device per unit volume.

[0031] 2. This invention utilizes the semi-magnetic characteristics of a functional composite skeleton. The scheme establishes a parallel current shunting mechanism in the magnetic circuit design. Under low current conditions, magnetic flux preferentially flows through the magnetic core component with higher permeability. When the current increases, causing the magnetic core component to approach saturation, the functional composite skeleton with semi-magnetic characteristics becomes a secondary channel for magnetic flux overflow. This automatic current shunting mechanism based on reluctance difference allows the inductance of the device to decrease gradually with increasing current, avoiding the hard saturation and precipitous drop in inductance that occurs with traditional air-gap inductors under overload, significantly enhancing the stability of the power supply system under transient high-current impacts.

[0032] 3. This invention achieves mechanical self-locking without adhesives by precisely fitting the limiting slots on the side of the stepped positioning ribs with the flat copper wires. After the flat copper wires are embedded in the limiting slots, their axial displacement is rigidly limited by the sidewalls of the ribs. At the same time, the L-shaped inverted structure at the end of the stepped positioning ribs further constrains the radial expansion freedom of the 3D precision interlocking winding. This three-dimensional mechanical locking structure greatly improves the overall rigidity of the winding, eliminates coil displacement caused by magnetostriction or external high-frequency vibration, fundamentally suppresses the howling noise during inductor operation, and improves the mechanical reliability of the device in harsh vibration environments such as automotive applications.

[0033] 4. The stepped positioning ribs of this invention not only serve to fix and dissipate heat, but their physical existence also forcibly defines the inter-turn distance and inter-layer distance of the 3D precision interlocking windings. This precise geometric separation significantly reduces the parasitic capacitance between windings, thereby improving the self-resonant frequency of the finished product. In addition, the presence of soft magnetic powder in the composite material helps to constrain the high-frequency magnetic field, reduce the electromagnetic interference of leakage flux on the surrounding circuits, and improve the electromagnetic compatibility performance of the device.

[0034] 5. The present invention performs nano-carbon tube spraying or oxidation blackening treatment on the surface of the packaged device, which greatly improves the infrared radiation emissivity of the device surface. In a closed space where natural convection is limited, this treatment enables the heat conducted to the device surface to be dissipated to the surrounding environment more efficiently in the form of infrared radiation, forming a complete heat dissipation closed loop of internal radial heat conduction plus external surface heat radiation, further ensuring the long-term reliable operation of the device under high temperature conditions. Attached Figure Description

[0035] The present invention will be further explained below with reference to the accompanying drawings and embodiments:

[0036] Figure 1 This is a schematic diagram of the overall external structure of the device;

[0037] Figure 2 This is a schematic diagram of the separated structure of the magnetic core assembly;

[0038] Figure 3 This is a schematic diagram of a 3D precision interlocking winding and its connection structure;

[0039] Figure 4 This is a flowchart of the method of the present invention;

[0040] In the diagram: 1. Functional composite frame; 2. Central shaft column; 3. Stepped positioning ribs; 4. Limiting slot; 5. L-shaped inverted structure; 6. 3D precision interlocking winding; 7. Flat copper wire; 8. Magnetic core assembly; 9. Metallized pads; 10. Thermally conductive boss; 11. Pins. Detailed Implementation

[0041] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to specific embodiments.

[0042] Example 1:

[0043] Please see Figures 1-4 A method for manufacturing 3D inductors based on Ampere's law, comprising:

[0044] S1. A functional composite frame 1 and a 3D precision interlocking winding 6 are set at the geometric center of the magnetic core assembly 8. The functional composite frame 1 includes a central shaft column 2 and multiple stepped positioning ribs 3 that extend radially outward and have axial limiting grooves 4 on the side.

[0045] S2. A functional composite skeleton 1 is formed by mixing a thermally conductive and insulating matrix with soft magnetic powder, so that it has semi-magnetic and thermally conductive characteristics.

[0046] S3. Flat copper wires 7 are sequentially inserted into the limiting slots 4 as 3D precision interlocking windings 6, and the air gaps between winding layers are filled by stepped positioning ribs 3.

[0047] S4. Assemble the components by inserting the stepped positioning ribs 3 deep into the 3D precision interlocking winding 6 to establish a low thermal resistance output path, and wrap the magnetic core assembly 8 around the functional composite skeleton 1 and the 3D precision interlocking winding 6 to establish a closed main magnetic circuit.

[0048] S5. Package and post-process the assembled device to form a finished inductor with anisotropic magnetic-thermal characteristics.

[0049] In this embodiment, the aim is to solve the thermal islanding effect and magnetic saturation problem under high current in existing high-power inductors; the manufacturing method constructs an anisotropic magnetic-thermal embedded array architecture;

[0050] In step S1, the defined functional composite skeleton 1 differs from traditional bakelite or LCP plastic skeletons. Its physical structure is configured as an active control component for heat flow and magnetic flow. The central shaft column 2 serves as the main support, and its multiple stepped positioning ribs 3 extending radially outward can be 4, 6, or 8, preferably 8, to evenly distribute thermal stress and form a probe structure for heat conduction. The dimensional tolerance of the limiting slot 4 is controlled within ±0.02mm to match the thickness of the flat copper wire 7.

[0051] In step S2, the skeleton is given specific physical properties through the proportion of composite materials; the semi-magnetic characteristic refers to the skeleton having a permeability higher than that of air but lower than that of the main magnetic core. Specifically, it refers to its relative permeability under test conditions of 100kHz and 0.1V, using an impedance analyzer with a special test fixture according to the IEC62044-2 standard. The range is It includes endpoint values, used to shunt magnetic flux during the magnetic saturation stage; thermal conductivity characteristics refer to the high thermal conductivity of the skeleton material, used to replace the air gap for heat conduction;

[0052] In step S3, the flat copper wire 7 is installed by physical embedding. Unlike traditional layered winding, this embodiment uses stepped positioning ribs 3 to fill the gaps between coil turns and layers. This structure replaces the original air layer with high thermal resistance with a solid material with high thermal conductivity, so that the inner side and upper and lower surfaces of each coil turn are in direct contact with the frame.

[0053] In step S4, two physical paths are established. In terms of thermal flow, the Joule heat generated inside the coil does not pass through the external insulation layer, but is directly transmitted radially to the positioning rib inserted deep into the coil and is discharged along the rib. In terms of magnetic flow, the main magnetic core constitutes a low magnetic resistance main circuit, while the functional composite skeleton 1 constitutes a parallel auxiliary magnetic circuit.

[0054] In step S5, by encapsulating and protecting the device structure, the anisotropy of the final product is manifested in the following ways: thermally, the radial thermal resistance is significantly lower than the axial thermal resistance, specifically in the radial thermal resistance... With axial thermal resistance The ratio satisfies This eliminates the situation where the coil center temperature is higher than the surface temperature. The above describes the thermal islanding effect; magnetically, the main magnetic circuit and bypass magnetic reluctance exhibit nonlinear complementary characteristics as current changes.

[0055] Step S1 includes the following:

[0056] S1.1 By constructing a magneto-thermal physical model, with the optimization goals of improving the soft saturation characteristics under high current and reducing the core temperature inside the coil, the permeability parameters of the functional composite skeleton 1 and the geometric topological parameters of the stepped positioning ribs 3 are simulated and calculated.

[0057] In this embodiment, a multiphysics simulation step is introduced to achieve precise design of device performance; the magneto-thermal physical model is a digital model constructed based on finite element analysis; during the optimization process, soft saturation characteristics are set as the first objective function, that is, the slope of the curve of inductance L changing with current I is required to remain smooth without a sudden drop in inflection point; specifically, the inductance is constructed... Regarding current The second derivative constrained model, setting the objective function Conditions met:

[0058] ;

[0059] in, For example, a preset smoothness threshold. This threshold is based on the device's rated inductance. to To solve the above model, this embodiment uses Ansys Maxwell or COMSOL Multiphysics for 3D finite element transient field simulation. The simulation boundary conditions are set as follows: the coil domain is set as a current source excitation, using insulated boundary conditions; the solution domain periphery is set as a balloon boundary to simulate an infinite space; in mesh generation, adaptive mesh refinement is used for the stepped positioning ribs 3 and the air gap region, and the maximum mesh size is limited to [specific dimensions to be filled in]. The model aims to capture local magnetic saturation effects; it utilizes a hybrid magnetoresistance formula and a parallel magnetic circuit model for solution.

[0060] ;

[0061] in, For the nonlinear reluctance of the magnetic core, The constant magnetic reluctance of the functional composite framework 1; where, The number of turns of the coil. The effective magnetic circuit length of the functional composite framework 1 is... The relative permeability of the functional composite framework 1, Let be the free permeability, and take a value of . , The effective magnetic circuit cross-sectional area of ​​the functional composite framework 1; by adjusting the relative permeability of the framework This makes the magnetic reluctance of the magnetic core... Within the range of sharp increases, the rate of change of total magnetic reluctance is... Clamping;

[0062] Based on this objective, the optimal relative permeability range of the functional composite framework 1 was calculated, for example... Set between 10 and 50, among which The relative permeability of the functional composite frame 1 is indicated to ensure that the frame can effectively share the leakage flux when the main magnetic core is saturated.

[0063] The second objective function is to reduce the core temperature inside the coil. The geometric topological parameters of the stepped positioning ribs 3 are determined through iterative calculations. These parameters include the rib thickness, extension length, and circumferential distribution density. The calculation logic is as follows: increasing the rib thickness reduces thermal resistance but reduces the winding space of the copper wire, increasing DC resistance. A balance between these two factors is sought through simulation, establishing a multi-objective optimization function.

[0064] ;

[0065] In the formula, the weighting coefficient and Dynamically adjust according to the application scenario; in automotive applications, due to extremely high heat dissipation requirements, the settings are... Values to , Values to In industrial control scenarios where energy efficiency requirements are even higher, setting... Values to , Values to This weighted method ensures the thickness of the designed ribs. It can satisfy the optimal solution under specific working conditions; among them, The rib thickness is a variable, in meters (m). The maximum allowable thermal resistance or normalized reference thermal resistance is given in K / W. To design the maximum permissible DC resistance value or normalized reference resistance, the unit is... In this formula, the thermal resistance model is defined as:

[0066] ;

[0067] in, The thermal conductivity of the material is expressed in W / (m·K). The heat transfer cross-sectional area is determined by the thickness. , Let m be the equivalent heat conduction path length from the center of the coil heat source to the heat dissipation surface; the DC resistance model is defined as:

[0068] ;

[0069] in, Area of ​​the skeleton window , The resistivity of copper wire , The number of coil turns. Let m be the average length of a single-turn coil. The thickness of the stepped positioning rib 3 is a variable, expressed in meters (m). The total height m of the stepped positioning rib 3 within the window section is the sum of the heights of all ribs, used to calculate the window area occupied by the ribs. The product term represents the total solid area occupied by all the stepped positioning ribs 3 within the skeleton window section, obtained by considering the area of ​​the skeleton window. deducting from The product term accurately calculates the effective space allowed for winding flat copper wires; the algorithm uses gradient descent to find this space. The minimum point is found, and the iteration termination condition is set as follows: This ensures that, under rated current, the temperature difference between the highest internal temperature point and the surface of the coil is controlled within a predetermined range, for example... ,in This represents the temperature difference between the highest temperature point inside the coil and the surface of the coil.

[0070] The stepped positioning rib 3 has an L-shaped buckle structure 5 at its end. In step S1.1, the optimization target also includes the coil displacement under mechanical vibration, and the geometric topology parameters include the depth of the limiting slot 4 and the size of the L-shaped buckle structure 5.

[0071] The L-shaped inverted buckle structure 5 includes a vertical arm connected to the end of the rib and an inwardly extending horizontal cantilever, the horizontal cantilever forming a semi-enclosed buckling space with the top surface of the rib; preferably, the length of the horizontal cantilever is... For flat copper wires with a width of 7 to Furthermore, the end of the cantilever is equipped with a guide chamfer, with a chamfer angle of [value missing]. to This allows the copper wire to slide in during winding;

[0072] In this embodiment, the mechanical structure of the frame is further optimized for high-vibration environments in automotive electronics or industrial control scenarios. The L-shaped inverted structure 5 is located at the outermost radial end of the rib, and its geometric feature is an inwardly curved hook-shaped protrusion or baffle. In the model optimization of S1.1, mechanical stress field simulation is introduced, and the coil displacement under mechanical vibration is set as a constraint condition, for example, the displacement is less than 0.01mm under 10G vibration. The calculation model for this constraint condition is based on cantilever beam bending theory, equating the L-shaped inverted structure 5 to a cantilever beam, with its maximum deflection... The calculation formula is:

[0073] ;

[0074] in, The vibrational inertial force N, For acceleration, take , The mass of the coil assembly is in kg. Let m be the length of the inverted cantilever. The Young's modulus (Pa) of the composite material. The moment of inertia of the L-shaped inverted structure 5 cantilever beam section about the neutral axis ; Ensure through calculation that during application During acceleration, This allows us to deduce the minimum thickness and cantilever length parameters of the undercut root.

[0075] Calculations determine that the depth of the limiting slot 4 needs to be slightly greater than the width of the flat copper wire 7, for example, through interference fit or micro-gap fit, where the gap value of the micro-gap fit is controlled within... to Between these elements, axial displacement of the coil is limited; simultaneously, the dimensions of the L-shaped inverted structure 5 are calculated to secure it to the outermost coil, limiting radial expansion or displacement. This design achieves mechanical self-locking without glue bonding, ensuring the device conforms to AEC-Q200 standards. to Displacement of the coil relative to the frame under vibration test This eliminates coil loosening noise caused by magnetostriction or external vibration;

[0076] In order to achieve the above in actual manufacturing to For the micro-gap fit, a shrinkage compensation factor for the composite material needs to be introduced during the mold design stage; for the aluminum nitride-based composite material in the following examples, its molding shrinkage is extremely low, approximately The mold cavity is machined using precision slow wire EDM, and the mold tolerance is controlled within [specific parameters]. The appropriate level, combined with the pressure holding process of the injection molding machine, can ensure the fitting accuracy during mass production;

[0077] The steps in S3 include:

[0078] Start the winding equipment and guide the flat copper wire 7 to the limit slot 4.

[0079] Tension is applied to embed the flat copper wire 7 into the limiting slot 4, and the axial displacement of the flat copper wire 7 is restricted by the stepped positioning ribs 3.

[0080] The radial displacement of the 3D precision interlocking winding 6 is restricted by the end structure of the stepped positioning rib 3, thereby achieving mechanical locking;

[0081] In this embodiment, the precision interlocking process between the coil and the bobbin is described in detail; the winding equipment is equipped with a precision tension controller to guide the flat copper wire 7 to the preset slot of the bobbin; in the tension application step, the tension is controlled to cause the copper wire to undergo a slight elastic deformation, thereby tightly embedding into the bottom of the limiting slot 4; at this time, the side wall of the stepped positioning rib 3 directly abuts against the wide surface of the copper wire, physically blocking the possibility of the copper wire sliding along the axial direction.

[0082] To address the brittleness issue of high-fill-rate aluminum nitride composites, the binder in step S2 is preferably a carboxyl-terminated butadiene-acrylonitrile rubber-toughened modified epoxy resin, which enhances the functional composite skeleton after curing. Possess at least The elongation at break is required to meet the requirements of the L-shaped inverted structure. The requirement for minimal elastic deformation during assembly is to prevent brittle fracture.

[0083] As the number of winding layers increases, when the outermost layer is wound, a turn of the coil is held in place by the end structure of the ribs, such as an L-shaped inverted buckle. Thus, the copper wire is rigidly constrained by mechanical components in the axial direction by the sidewalls of the ribs and in the radial direction by the bottom surface of the ribs and the end inverted buckle, achieving a mechanical locking state. This process not only ensures the stability of the structure, but also significantly reduces the interlayer parasitic capacitance through regular arrangement, thereby improving the self-resonant frequency of the device.

[0084] In step S1, the core assembly 8 is made of high-frequency, low-loss ferrite, and the permeability of the functional composite skeleton 1 is lower than that of the core assembly 8 but higher than that of air.

[0085] In this embodiment, the magnetic properties of each component are matched to achieve soft saturation; the magnetic core assembly 8 is selected from high-frequency, low-loss ferrite of the manganese-zinc (Mn-Zn) or nickel-zinc (Ni-Zn) system, with a relative permeability of Typically between 1000 and 3000; the relative permeability of functional composite framework 1 The configuration is significantly lower than that of the core assembly 8, but much higher than that of air in terms of relative permeability:

[0086] ; magnetic core reluctance

[0087] Magnetic core reluctance With relative permeability Inversely proportional, by setting The gradient ensures that the magnetic flux is confined within the main magnetic circuit before the core saturates, while when the core approaches saturation, the functional composite framework with semi-magnetic characteristics becomes a secondary channel for flux overflow; for example, configured to be 10 to 50; where, the symbol , and These represent the relative permeabilities of the magnetic core assembly 8, the functional composite frame 1, and air, respectively. The principle behind this permeability gradient is to utilize the difference in magnetic reluctance to shunt magnetic flux: under low current conditions, the magnetic reluctance of the magnetic core is much smaller than that of the frame, and the magnetic flux preferentially flows through the magnetic core, resulting in high inductance of the device. When the current increases and the magnetic core tends to saturate, the magnetic reluctance rises sharply, while the magnetic reluctance of the frame becomes relatively low, and the newly added magnetic flux automatically overflows and flows through the semi-magnetic frame. This mechanism avoids the precipitous drop in inductance caused by the direct dispersion of magnetic flux into the air, physically flattens the saturation inflection point of the magnetization curve, and achieves smooth decay of inductance under high current.

[0088] In step S2, the composite material is formulated with 60% to 80% by mass of high thermal conductivity and electrical insulating ceramic powder, 10% to 20% by mass of soft magnetic powder, and a binder. The aluminum nitride powder has a particle size of 10-50 μm. ;

[0089] In this embodiment, the specific material formulation of the functional composite framework 1 is disclosed to balance thermal conductivity, insulation, and magnetism; aluminum nitride (AlN) powder is selected as the thermally conductive and insulating matrix, with a mass ratio of 70%; aluminum nitride is chosen because it has extremely high thermal conductivity, theoretically reaching 320 W / m·K, and excellent insulation properties; the particle size is limited to 10-50 μm. This is to ensure the filler density during injection molding and to form a continuous heat conduction network;

[0090] Sendust magnetic powder, composed of iron-silicon-aluminum alloy, is selected as the functional filler, accounting for 15% by mass. Iron-silicon-aluminum alloy possesses high saturation magnetic induction and low loss characteristics, imparting the required semi-magnetic properties to the framework. The remaining portion is a high-strength binder, such as epoxy resin or PPS. Specifically, the binder is preferably a low-viscosity, high-temperature resistant epoxy resin system with a glass transition temperature (Tg) greater than [value missing]. To address the compatibility issues between high-proportion inorganic powders, such as aluminum nitride and iron-silicon-aluminum, and organic binders, the powder surface is pre-treated with a silane coupling agent, such as KH-560. The amount of coupling agent used is [amount missing]% of the powder mass. to The mixing process employs a planetary vacuum mixer, operating at a vacuum level. Rotation speed Stirring under the conditions This is done to eliminate internal microbubbles and ensure the compactness of the composite material after curing.

[0091] Regarding the mechanism of semi-magnetic characteristics: Ferro-silicon-aluminum magnetic powder exhibits a dispersed distribution within an insulating aluminum nitride matrix; when the magnetic powder content is... At this time, the magnetic powder particles are separated by the insulating matrix and binder, failing to form a continuous magnetic conductive path, thus exhibiting low magnetic permeability. It also exhibits high saturation magnetic flux density; this microstructure is similar to a distributed air-gap magnetic core, effectively preventing localized magnetic flux concentration; this ratio has been experimentally verified to ensure that the thermal conductivity of the frame is greater than [value missing]. It can provide suitable magnetic permeability while maintaining sufficient mechanical strength to withstand winding tension;

[0092] The functional composite skeleton 1 is formed by high-pressure injection molding or powder metallurgy. The thermal conductivity of the functional composite skeleton 1 is greater than that of the composite skeleton 1. ;

[0093] This embodiment details the molding process and key thermal properties of the skeleton. High-pressure injection molding or powder metallurgy is used to ensure the density of the high-filling-rate composite material. Under high pressure, the aluminum nitride particles in the composite material form a tight contact interface, minimizing internal porosity, which is a poor conductor of heat. Specific process parameters include: the injection molding machine barrel temperature is set to... to Mold temperature controlled at to Injection pressure set to to Holding time to If powder metallurgy is used, the forming pressure needs to be greater than [a certain value]. And under a nitrogen protective atmosphere Perform heat curing treatment;

[0094] The resulting functional composite framework 1 has a measured thermal conductivity greater than [missing value]. Based on ASTM D5470 standard, in Tested at ambient temperature; regarding the radial thermal resistance to axial thermal resistance ratio mentioned in Example 1. The verification was based on the transient dual-interface method of the JEDEC JESD51-14 standard.

[0095] Experimental data show that, Under DC current loading, the highest internal temperature of the inductor using the frame of this embodiment is... With surface center temperature temperature difference Only , here The coil surface temperature in Example 2 is much lower than that of traditional bakelite frame inductors. The temperature difference strongly confirms the elimination of the heat island effect;

[0096] Compared to traditional bakelite frames with a thermal conductivity of approximately 0.2-0.5 W / m·K, the thermal conductivity of the frame in this embodiment is increased by hundreds of times. This indicator ensures that when the frame ribs come into contact with the coil heat source, heat can be transferred quickly with extremely low thermal resistance, making the frame effectively a heat sink embedded inside the coil.

[0097] The steps in S5 include:

[0098] Vacuum encapsulation of the entire device;

[0099] The surface of the device is coated with carbon nanotubes or oxidized and blackened to make the infrared emissivity of the device surface greater than 0.9.

[0100] The coating thickness of the carbon nanotube coating is controlled within to Between; too thin and the emissivity will not be significantly improved, while too thick and the emissivity may be too thick and the coating may peel off due to the mismatch of the coefficients of thermal expansion; the coating must pass the cross-cut adhesion test, standard ISO2409, and reach level 0 or 1 to ensure that it does not peel off under thermal shock environment;

[0101] In this embodiment, step S5 further improves thermal management efficiency by enhancing radiative heat dissipation; vacuum potting uses high thermal conductivity epoxy resin to fill any tiny air gaps that may remain inside the device, ensuring the integrity of the structure and its waterproof and dustproof capabilities; the nano-carbon tube spraying or oxidation blackening treatment is intended to change the optical properties of the device surface; the infrared emissivity of ordinary metal or plastic surfaces is low, which is not conducive to thermal radiation.

[0102] Through the above treatment, the infrared emissivity of the surface is increased to The above is the test wavelength range. to Test temperature According to the Stefan-Boltzmann law, radiative heat dissipation power is proportional to emissivity. In closed, fanless passive heat dissipation environments such as automotive ECUs, this treatment enables the device to more efficiently dissipate the heat conducted to the surface into the surrounding space in the form of infrared radiation, forming a complete heat dissipation closed loop of internal conduction + surface radiation.

[0103] Example 2:

[0104] Please see Figures 1-3 A 3D inductor based on Ampere's law, comprising:

[0105] A functional composite frame 1 is positioned at the geometric center of the 3D inductor;

[0106] The 3D precision interlocking winding 6 is set on the outside of the functional composite frame 1 through physical fitting;

[0107] The magnetic core assembly 8 is wrapped around the 3D precision interlocking winding 6 and the functional composite frame 1. The functional composite frame 1 is a semi-magnetic entity containing a thermally conductive insulating matrix and soft magnetic powder. The functional composite frame 1 is provided with stepped positioning ribs 3 that are inserted into the gap of the 3D precision interlocking winding 6.

[0108] In this embodiment, the specific hardware structure of the inductor obtained by the above method is described; the functional composite skeleton 1 is in the core position and serves as the mounting carrier for each component; its material properties, semi-magnetism, high thermal conductivity and geometric structure are the key to achieving the technical effect of the present invention.

[0109] The 3D precision interlocking winding 6 is fixed by physical interlocking; here, interlocking means that the flat copper wire 7 is separated and clamped by the stepped positioning ribs 3 of the skeleton, rather than simply winding; this structure makes the mechanical stability of the coil no longer dependent on the adhesive force of the insulating varnish.

[0110] The magnetic core assembly 8 is covered on the outside to form a closed magnetic circuit. It is worth noting that the stepped positioning ribs 3 of the skeleton not only serve to support the coil, but their physical part also fills the air gap between the layers of the traditional coil, dividing the coil into multiple heat dissipation units. Each unit is in direct contact with the heat-conducting skeleton, thereby completely eliminating the heat accumulation points deep in the coil.

[0111] The bottom of the functional composite skeleton 1 is provided with a metallized pad 9 or a heat-conducting boss 10. The metallized pad 9 or the heat-conducting boss 10 is thermally connected to the stepped positioning rib 3. The pin 11 of the 3D precision interlocking winding 6 is connected to the metallized pad 9.

[0112] In this embodiment, the thermal and electrical external interface structure of the device is described; the bottom of the functional composite skeleton 1 is provided with metallized pads 9 or thermally conductive bosses 10; these structures are not independent attachments, but are physically integrally formed or tightly connected with the stepped positioning ribs 3 of the skeleton body, forming a continuous heat conduction path.

[0113] During operation, the heat from the coil enters the ribs and is transferred downwards along the ribs to the heat-conducting boss 10 at the bottom. When the inductor is soldered onto the PCB, the heat-conducting boss 10 directly contacts the heat-dissipating copper foil of the PCB. At the same time, the copper wire pins 11 of the 3D precision interlocking winding 6 are connected to the metallized pads 9 by thermoforming or laser welding, which not only achieves electrical conduction but also assists in heat dissipation. This design directly pumps the heat inside the inductor to the external circuit board and uses the large area of ​​copper foil on the PCB for auxiliary heat dissipation, which significantly reduces the thermal resistance of the device.

[0114] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention.

Claims

1. A method of manufacturing a 3D inductor based on Ampere's law, characterized by, include: S1. A functional composite skeleton (1) and a 3D precision interlocking winding (6) are set at the geometric center of the magnetic core assembly (8); the functional composite skeleton (1) includes a central shaft column (2) and a plurality of stepped positioning ribs (3) that extend radially outward and have axial limiting grooves (4) on the side. S2. The functional composite skeleton (1) is formed by mixing a thermally conductive and insulating matrix with soft magnetic powder, so that it has semi-magnetic and thermally conductive characteristics. S3. Flat copper wire (7) is used as a 3D precision interlocking winding (6) and is sequentially inserted into the limiting slot (4). The air gap between winding layers is filled by the stepped positioning ribs (3). S4. Assemble the device, insert the stepped positioning rib (3) deep into the 3D precision interlocking winding (6) to establish a low thermal resistance output path, and wrap the magnetic core assembly (8) around the functional composite skeleton (1) and the 3D precision interlocking winding (6) to establish a closed main magnetic circuit. S5. Package and post-process the assembled device to form a finished inductor with anisotropic magnetic-thermal characteristics. Step S1 includes the following: S1.1 By constructing a magneto-thermal physical model, with the optimization goal of improving the soft saturation characteristics under high current and reducing the core temperature inside the coil, the permeability parameters of the functional composite skeleton (1) and the geometric topology parameters of the stepped positioning ribs (3) are simulated and calculated. The formula for calculating geometric topological parameters is: ； in, and These are the weighting coefficients; For rib thickness, the unit is meters (m). The maximum allowable thermal resistance or normalized reference thermal resistance is given in K / W. To design the maximum permissible DC resistance value or normalized reference resistance, the unit is... ; Thermal resistance model Defined as: ； in, The thermal conductivity of the material is expressed in W / (m·K). The heat transfer cross-sectional area is determined by the thickness. , Let m be the equivalent heat conduction path length from the center of the coil heat source to the heat dissipation surface; DC resistance model Defined as: ； in, Area of ​​the skeleton window ; The resistivity of copper wire ; This refers to the number of coil turns. The average length m of a single-turn coil; The total height m of the stepped positioning rib (3) within the window section; The product term represents the total solid area occupied by all the stepped positioning ribs (3) within the skeleton window section; by the area of ​​the skeleton window deducting from The product term calculates the effective space allowed for winding flat copper wires; the algorithm uses gradient descent to find this space. The minimum point is found, and the iteration termination condition is set as follows: This ensures that, under rated current, the temperature difference between the highest temperature point inside the coil and the surface is controlled within a predetermined range, such as... ,in This indicates the temperature difference between the highest temperature point inside the coil and the surface of the coil.

2. The method for manufacturing a 3D inductor based on Ampere's law according to claim 1, characterized in that, The stepped positioning rib (3) has an L-shaped buckle structure (5) at its end. In step S1.1, the optimization target also includes the coil displacement under mechanical vibration, and the geometric topology parameters include the depth of the limiting slot (4) and the size of the L-shaped buckle structure (5).

3. A method for manufacturing a 3D inductor based on Ampere's law according to any one of claims 1 to 2, characterized in that, The steps in S3 include: Start the winding equipment and guide the flat copper wire (7) to the limit slot (4); Tension is applied to embed the flat copper wire (7) into the limiting slot (4), and the axial displacement of the flat copper wire (7) is restricted by the stepped positioning ribs (3); Mechanical locking is achieved by using the end structure of the stepped positioning rib (3) to restrict the radial displacement of the 3D precision interlocking winding (6).

4. A method for manufacturing a 3D inductor based on Ampere's law according to any one of claims 1 to 2, characterized in that, In step S1, the core assembly (8) is made of high-frequency low-loss ferrite, and the permeability of the functional composite skeleton (1) is lower than that of the core assembly (8) but higher than that of air.

5. A method for manufacturing a 3D inductor based on Ampere's law according to any one of claims 1 to 2, characterized in that, In step S2, the composite material is formulated with 60% to 80% aluminum nitride powder, 10% to 20% iron-silicon-aluminum magnetic powder, and a binder by mass ratio. The aluminum nitride powder has a particle size of 10-50 μm. .

6. A method for manufacturing a 3D inductor based on Ampere's law according to any one of claims 1 to 2, characterized in that, The functional composite skeleton (1) is formed by high-pressure injection molding or powder metallurgy. The thermal conductivity of the functional composite skeleton (1) is greater than that of the composite skeleton (1). .

7. A method for manufacturing a 3D inductor based on Ampere's law according to any one of claims 1 to 2, characterized in that, The steps in S5 include: Vacuum encapsulation of the entire device; The surface of the device is coated with carbon nanotubes or oxidized and blackened to make the infrared emissivity of the device surface greater than 0.

9.

8. A 3D inductor based on Ampere's law, applied to the manufacturing method of a 3D inductor based on Ampere's law as described in any one of claims 1 to 7, characterized in that, include: A functional composite frame (1) is set at the geometric center of the 3D inductor; The 3D precision interlocking winding (6) is set outside the functional composite skeleton (1) by physical fitting; The magnetic core assembly (8) is wrapped around the periphery of the 3D precision interlocking winding (6) and the functional composite skeleton (1). The functional composite skeleton (1) is a semi-magnetic entity containing a thermally conductive insulating matrix and soft magnetic powder. The functional composite skeleton (1) is provided with stepped positioning ribs (3) that are inserted into the gap of the 3D precision interlocking winding (6).

9. A 3D inductor based on Ampere's law according to claim 8, characterized in that, The bottom of the functional composite skeleton (1) is provided with a metallized pad (9) or a heat-conducting boss (10). The metallized pad (9) or the heat-conducting boss (10) is thermally connected to the stepped positioning rib (3). The pin (11) of the 3D precision interlocking winding (6) is connected to the metallized pad (9).

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