UI differential mode inductance

Abstract

The utility model discloses a UI shape difference mode inductance, include: magnetically conductive component, winding coil, air gap adjusting component, heat conduction component, insulating component and product base, the magnetically conductive component is by U shape magnetic core and I shape magnetic core mutual inlay and constitutes the magnetic circuit closed structure, the winding coil is set up in the recess of U shape magnetic core, and realizes electrical isolation through insulating component and magnetic core, the heat conduction component contains the heat conduction silica gel pad of setting in magnetically conductive component bottom, is used for conducting heat from the magnetic core to product base, the air gap adjusting component contains the air gap adjusting structure of setting in I shape magnetic core and U shape magnetic core contact surface, product base fixed connection magnetically conductive component and heat conduction component, wherein, the recess width size of U shape magnetic core is less than I shape magnetic core cross section width, and the insulating component is at least covered in I shape magnetic core surface.

Description

Technical Field

[0001] This utility model belongs to the field of power electronic magnetic components technology, specifically relating to a differential mode inductor design for use in EMI filter circuits of switching power supplies, which is particularly suitable for scenarios with stringent requirements for size, power density and saturation current (such as power supply modules for charging piles, power supply modules for new energy vehicles, power supply modules for new energy photovoltaics, power supply modules for servers, etc.). Background Technology

[0002] In switching power supply design, differential mode inductors are key components of EMI filters, requiring them to simultaneously meet the core requirements of high inductance, low loss, small size, and efficient heat dissipation. Traditional differential mode inductors commonly employ EE, EQ, or block core structures. While these structures are technically mature, they have inherent drawbacks: low space utilization, redundant width in the core pillars leading to a large overall size; inadequate heat dissipation paths, requiring coil heat to be conducted to the core through air gaps or insulating frames, resulting in high thermal resistance and limiting power density improvements; furthermore, air gap adjustment is typically located in the core pillars, requiring high machining precision and potentially affecting the core's mechanical strength.

[0003] To address these issues, the industry has explored various solutions, such as using low-loss core materials or optimizing winding structures. However, these improvements often face constraints between size reduction and enhanced heat dissipation, and between cost reduction and performance improvement, making it difficult to achieve a comprehensive balance. The UI-shaped core structure has been proposed as an alternative, theoretically shortening the magnetic circuit length and reducing volume through a combination of a U-shaped yoke and an I-shaped core. However, existing UI-shaped inductor designs still require further innovation and improvement in areas such as achieving efficient thermal management of the coil and core, ensuring reliable electrical insulation, and simplifying the air gap adjustment process. Utility Model Content

[0004] To address the aforementioned technical problems, this utility model proposes a UI-shaped differential mode inductor to solve the issues of large size, low heat dissipation efficiency, inconvenient air gap adjustment, and high cost of existing differential mode inductors.

[0005] The present invention adopts the following technical solution: A UI-shaped differential mode inductor includes: a magnetic conductive component, a winding coil, an air gap adjustment component, a heat-conducting component, an insulating component, and a product base; the magnetic conductive component consists of a U-shaped magnetic core and an I-shaped magnetic core interlocking to form a closed magnetic circuit structure; the winding coil is disposed within the groove of the U-shaped magnetic core and is electrically isolated from the magnetic core by the insulating component; the heat-conducting component includes a thermally conductive silicone pad disposed at the bottom of the magnetic conductive component for conducting heat from the magnetic core to the product base; the air gap adjustment component includes an air gap adjustment structure disposed at the contact surface of the I-shaped magnetic core and the U-shaped magnetic core; the product base is fixedly connected to the magnetic conductive component and the heat-conducting component; wherein, the groove width of the U-shaped magnetic core is smaller than the cross-sectional width of the I-shaped magnetic core, and the insulating component at least covers the surface of the I-shaped magnetic core.

[0006] In some embodiments, the following technical features are also included: The winding coil has a multi-layer flat conductor structure and contains at least two pairs of winding groups.

[0007] In some embodiments, the following technical features are also included: The air gap adjustment structure includes a gap control layer disposed between the first magnetically conductive component and the second magnetically conductive component.

[0008] In some embodiments, the following technical features are also included: The gap control layer includes an air gap gasket.

[0009] In some embodiments, the following technical features are also included: The thickness of the air gap gasket is set in an inverse relationship with the magnetic saturation parameter of the I-shaped magnetic core.

[0010] In some embodiments, the following technical features are also included: The insulating component includes an insulating skeleton molded from engineering plastic, the inner wall of which has a stepped anti-displacement structure.

[0011] In some embodiments, the following technical features are also included: The thermal conductivity of the thermally conductive silicone pad is in the range of 1.2-3.5 W / m·K, and the contact area with the bottom of the U-shaped magnetic core accounts for no less than 80%.

[0012] In some embodiments, the following technical features are also included: The winding coil comprises multiple independent windings, which are arranged in parallel within the concave cavity.

[0013] In some embodiments, the following technical features are also included: The thickness of the thermally conductive silicone pad ranges from 0.5 to 1.5 mm.

[0014] In some embodiments, the following technical features are also included: An insulating pad is provided between the bottom of the U-shaped magnetic core and the thermally conductive silicone pad to enhance electrical isolation and assist in heat conduction.

[0015] Compared with the prior art, the beneficial effects of this utility model are as follows: The core advantages of this invention lie in the comprehensive optimization of differential mode inductors in terms of miniaturization, heat dissipation performance, manufacturability, and cost-effectiveness achieved through the coordinated design and layout of the magnetic conductive component, heat dissipation component, insulation component, and air gap adjustment component. Specifically, the magnetic conductive component, composed of U-shaped and I-shaped magnetic cores, forms a shorter magnetic circuit than the traditional EE-shaped component, directly contributing to the reduction in size. The winding coil is directly embedded in the groove of the U-shaped magnetic core and in close contact with the thermally conductive silicone pad, constructing an efficient heat conduction path from the coil to the magnetic core and then to the external environment. This path significantly reduces thermal resistance by replacing the low thermal conductivity air layer with a high thermal conductivity silicone pad, thereby greatly improving heat dissipation capacity. The improved heat dissipation capacity allows the use of winding conductors with smaller cross-sectional areas under the same temperature rise limit, achieving a reduction in material costs. At the same time, the air gap adjustment structure is set on the contact plane of the I-shaped and U-shaped magnetic cores and adjusted through the air gap pad, making the adjustment of inductance simple, precise, and reliable, improving the manufacturability and consistency of the product. Ultimately, the synergistic effect of the aforementioned technical features enables this invention to reduce size while effectively improving heat dissipation efficiency and lowering overall costs.

[0016] Furthermore, using a multi-layered flat conductor structure for the winding coil helps reduce the coil's AC resistance and proximity effect losses, thereby improving the inductor's efficiency.

[0017] Furthermore, by setting a gap control layer that includes air gap gaskets, precise and convenient control of the air gap is achieved.

[0018] Furthermore, the reverse correlation setting between the air gap shim thickness and the magnetic saturation parameter allows the inductance adjustment to match the electrical performance of the magnetic core, thus optimizing the inductor's operating characteristics.

[0019] Furthermore, the stepped anti-displacement structure on the inner wall of the insulating frame enhances the stability of the assembled structure and prevents the components from shifting under vibration.

[0020] Furthermore, the limitations on the thermal conductivity and contact area of ​​the thermally conductive silicone pad ensure that its thermal conductivity meets the requirements of high power density applications.

[0021] Furthermore, the configuration of multiple independent windings makes the inductor suitable for complex circuit scenarios requiring multi-channel filtering.

[0022] Furthermore, limiting the thickness of the thermally conductive silicone pad ensures good thermal conductivity while also taking into account the product's structural strength and assembly processability.

[0023] Furthermore, an insulating pad is added between the bottom of the U-shaped magnetic core and the thermally conductive silicone pad, which further enhances the electrical safety of the system. Attached Figure Description

[0024] Figure 1 This is a three-dimensional exploded view of the UI shape difference inductor of this utility model.

[0025] Figure 2 This is an assembly cross-sectional view of the UI-shaped differential inductor of this utility model.

[0026] Figure 3 This is a perspective view of the UI-shaped differential inductor of this utility model.

[0027] Explanation of reference numerals in the attached drawings: 1. Product base; 2. U-shaped magnetic core; 21. U-shaped groove; 3. I-shaped magnetic core; 4. Winding coil; 5. Thermally conductive silicone pad; 6. Insulating frame; 7. Air gap gasket; 8. Insulating gasket. Detailed Implementation

[0028] The embodiments of this utility model are described in detail below. It should be emphasized that the following description is merely exemplary and not intended to limit the scope and application of this utility model.

[0029] It should be noted that when a component is referred to as "fixed to" or "set on" another component, it can be directly on or indirectly on that other component. When a component is referred to as "connected to" another component, it can be directly connected to or indirectly connected to that other component. Furthermore, a connection can be used for both fixing and circuit / signal connectivity.

[0030] It should be understood that the terms "length", "width", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", and "outer" 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 the embodiments of 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.

[0031] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of embodiments of this utility model, "a plurality of" means two or more, unless otherwise explicitly specified.

[0032] The basic concept of the following embodiments of this utility model is as follows: This utility model relates to a UI shape difference mode inductor: The specific structure is as follows: Figure 1-3 As shown, UI-shaped differential mode inductors use a UI-shaped magnetic core structure, resulting in a smaller PCB footprint, making them particularly suitable for high power density layouts.

[0033] The UI-shaped winding is fully embedded in the groove 21 of the U-shaped magnetic core 2. After the base 1 cover plate is pressed, a closed structure is formed with no external protrusion. The winding coil 4 is electrically isolated from the U-shaped magnetic core 2 through the insulating pad 8. At the same time, heat is conducted to the U-shaped magnetic core 2 through the insulating pad 8, and then to the product base 1 through the thermally conductive silicone pad 5, achieving efficient heat dissipation without the need for additional insulation distance. The winding coil 4 is electrically isolated from the U-shaped magnetic core 2 through the insulating pad 8, and at the same time, it is in close contact to facilitate heat conduction. It has high integration, reduces ineffective space, and has high winding space utilization.

[0034] There is an insulating frame 6 between the I-shaped magnetic core 3 and the winding coil 4, and an insulating pad 8 between the winding coil 4 and the magnetic core 2.

[0035] The air gap is located between the I-shaped magnetic core 3 and the U-shaped magnetic core 2 (planar air gap), and can be precisely controlled by adjusting the thickness of the air gap shim 7 without increasing the size of the magnetic core.

[0036] This invention is not limited to a single winding, but can also include multiple windings.

[0037] UI shape is just a two-dimensional shape; the details of U and I can also be multiple shapes.

[0038] The implementation method and operation steps are as follows: Step 1: Make a winding jig according to the shape requirements of the three-dimensional coil. The width of the mandrel of the winding jig is 15.7mm and the axial height of the coil is 43mm.

[0039] Step 2: Wind the coil with flat wire of 4*5mm and 8 turns, and wrap the I-shaped magnetic core with an insulating frame.

[0040] Step 3: After insulating the I-shaped magnetic core, insert it into the coil, and place insulating pads and air gap pads on both sides.

[0041] Step 4: Apply epoxy G500 to both ends of the I-shaped core and bake at 120 degrees Celsius for 2 hours until cured. Place insulating pad 8 and thermally conductive silicone pad 5 inside the U-shaped core and assemble the U and I cores.

[0042] Step 5: Install the product into the product base.

[0043] The implementation of this technical solution can achieve the following technical effects: U-shaped + I-shaped magnetic core combination: Compared to traditional EE / EQ shaped magnetic cores, the UI-shaped magnetic core uses a U-shaped yoke to wrap the coil and an I-shaped magnetic core to close the magnetic circuit, reducing the width of the central column and making the overall magnetic core smaller, with a volume reduction of approximately 20%. See the table below.

[0044] Redundant frame design: The insulating frame retains only the necessary insulation ("insulating frame" in the figure). The coil is electrically isolated from the magnetic core 2 through the insulating pad 8, while maintaining close contact to facilitate heat conduction and reduce axial height.

[0045] Direct heat conduction of the magnetic core: The heat from the winding is conducted to the U-shaped magnetic core through the insulating pad 8, and then conducted to the base through the thermally conductive silicone pad 5.

[0046] To quantify the heat dissipation improvement effect, based on the thermal resistance formula R... θ =δ / (k×A) (where δ is the material thickness, k is the thermal conductivity, and A is the effective thermal conductivity area) is used for simulation calculation and comparison. Traditional EE-shaped inductor designs use an engineering plastic frame (typical thermal conductivity k≈0.25 W / m·K, thickness δ=0.5mm) to achieve insulation and fixation between the coil and the magnetic core. Its simulated thermal resistance is approximately R. θ,old This design eliminates the need for a separate frame, instead using a high thermal conductivity silicone pad (k=2.5 W / m·K, δ=1.0mm) to directly fill the gap between the coil and the bottom of the U-shaped magnetic core to establish a heat conduction path. Its simulated thermal resistance R... θ,new Significantly reduced. Calculations show that the overall thermal resistance from the heat source (coil) to the heat dissipation surface (mounting housing) is reduced by approximately 60%.

[0047] The improved heat dissipation capacity allows for the use of conductors with higher current densities under the same temperature rise constraints. Simulation and experimental verification show that traditional designs require 4mm×5mm flat copper wire (current density of approximately 5A / mm²), while this solution can use 2.9mm×5mm flat copper wire (current density of approximately 7A / mm²) while ensuring temperature rise, achieving a reduction of approximately 27.5% in copper usage and directly lowering material costs.

[0048] The beneficial effects of this embodiment are: Significantly reduced volume: Due to the adoption of a UI-shaped magnetic core structure (2,3), the redundant width of the central column in the traditional EE core is eliminated, resulting in a shorter magnetic circuit length le under the same effective cross-sectional area Ae, and the overall volume is reduced by about 20%, making it more suitable for high power density scenarios.

[0049] Significantly improved heat dissipation performance: Due to the adoption of a non-redundant frame design, the winding coil 4 directly or through the thermally conductive silicone pad 5 contacts the U-shaped magnetic core 2, establishing an efficient heat dissipation path. By replacing the air layer with the thermally conductive silicone pad 5, the thermal resistance is reduced by approximately 60%, solving the heat generation bottleneck.

[0050] Cost reduction: Improved heat dissipation allows for the use of smaller cross-sectional area copper wires while maintaining the same temperature rise, reducing copper costs by approximately 27.5% or more.

[0051] The air gap is easy to adjust: the air gap is located between the planes of the I-shaped magnetic core 3 and the U-shaped magnetic core 2. The inductance can be precisely controlled by replacing the air gap shims 7 of different thicknesses. The process is simple and reliable.

[0052] Example 2

[0053] Similar to Embodiment 1, this embodiment provides a UI-shaped differential mode inductor, the basic structure of which corresponds to the technical solution in the content section of the utility model. Specifically: The “magnetic guide assembly” is specifically composed of the following components: a U-shaped ferrite core (corresponding to “U-shaped core”) and a rectangular ferrite core (corresponding to “I-shaped core”).

[0054] A “winding coil” is specifically a coil made by winding a flat copper wire.

[0055] The "air gap adjustment assembly" and its included "air gap adjustment structure" are specifically one or more non-magnetic pads (corresponding to "air gap pads") disposed between the I-shaped magnetic core and the U-shaped magnetic core.

[0056] The “thermal conductive component” is specifically a pre-formed high thermal conductivity silicone pad (corresponding to “thermal conductive silicone pad”).

[0057] The “insulating assembly” specifically includes a plastic frame (corresponding to the “insulating frame”) that encloses the I-shaped magnetic core and may be supplemented with an insulating film or gasket.

[0058] The “product base” is specifically a plastic or metal bracket.

[0059] The specific technical defects addressed in this embodiment are the large size, high thermal resistance of the heat dissipation path, and inconvenience of air gap adjustment of traditional EE differential inductors.

[0060] Detailed technical solution: See also Figures 1 to 3The UI-shaped differential mode inductor in this embodiment also includes a product base 1, a U-shaped magnetic core 2, an I-shaped magnetic core 3, a winding coil 4, a thermally conductive silicone pad 5, an insulating frame 6, an air gap pad 7, and an insulating pad 8.

[0061] in: The U-shaped magnetic core 2 has an upward-opening groove (U-shaped groove 21). The winding coil 4 is placed and fixed in the U-shaped groove 21 of the U-shaped magnetic core 2. The thermally conductive silicone pad 5 is pasted on the bottom outer surface of the U-shaped magnetic core 2. The I-shaped magnetic core 3 is covered with the insulating skeleton 6. The air gap pad 7 is pasted on the top and / or bottom end face of the insulating skeleton 6. The insulating pad 8 can optionally be disposed between the bottom inner surface of the U-shaped magnetic core 2 and the winding coil 4, or at other locations where enhanced insulation is required.

[0062] An I-shaped magnetic core 3, covered with an insulating skeleton 6 and an air gap pad 7, is embedded into the groove 21 of a U-shaped magnetic core 2, forming a closed magnetic circuit together with the U-shaped magnetic core 2. The fitting dimensions of the groove 21 of the U-shaped magnetic core 2 and the I-shaped magnetic core 3 are precisely designed. The opening of the U-shaped magnetic core 2 is provided with a guide chamfer, and the insulating skeleton 6 of the I-shaped magnetic core 3 has a certain amount of elastic deformation. This ensures a tight fit to form a closed magnetic circuit while avoiding excessive assembly stress on the brittle ferrite core, preventing it from cracking. At this time, the air gap pad 7 is located at the contact interface between the I-shaped magnetic core 3 and the U-shaped magnetic core 2, forming the air gap.

[0063] Finally, the assembled magnetic core assembly is mounted and fixed onto the product base 1 using the thermally conductive silicone pad 5.

[0064] Dimensions: The U-shaped magnetic core 2 can be a ferrite core with a width W of approximately 25.0 mm, a height H of approximately 15.0 mm, and a length L of approximately 30.0 mm.

[0065] The winding coil 4 can be made by winding 6-10 turns of flat copper wire with a width of 3.0mm-5.0mm x 4.0mm-6.0mm (thickness).

[0066] The thickness of the thermally conductive silicone pad 5 can be 1.0 mm, and the thermal conductivity is preferably 2.0 W / m·K.

[0067] The thickness of the air gap gasket 7 can be selected according to the target inductance, such as 0.1mm, 0.2mm, 0.3mm, etc.

[0068] The insulating frame 6 can be molded from LCP engineering plastic with a wall thickness of approximately 0.5 mm.

[0069] Implementation steps (in chronological order): 1. Step 1 (Winding): Using a winding fixture with an inner diameter of 15.7mm, wind the flat copper wire 8 turns to form winding coil 4. The axial height of the coil is controlled at 43.0mm.

[0070] 2. Step Two (Insulation Treatment): Insert the I-shaped magnetic core 3 into the prefabricated insulating frame 6.

[0071] 3. Step Three (Pre-assembly): Attach an air gap gasket 7 of selected thickness to the designated end face of the insulating frame 6. Optionally, place an insulating gasket 8 in the groove of the U-shaped magnetic core 2.

[0072] 4. Step Four (Glue Application and Assembly): Apply epoxy glue G500 to the appropriate location on the I-shaped magnetic core 3 or the insulating frame 6. Embed the assembled I-shaped magnetic core 3 into the groove of the U-shaped magnetic core 2 where the winding coil 4 has been placed. Place the entire assembly in an oven at 120°C for 2 hours to cure.

[0073] 5. Step Five (Installation Base): Attach the thermally conductive silicone pad 5 to the bottom of the U-shaped magnetic core 2, and then install and fix the entire inductor assembly onto the product base 1.

[0074] The above-described embodiments are only used to illustrate the technical solutions of this utility model, and are not intended to limit it. Although this utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this utility model.

Claims

1. A UI-shaped differential inductor, characterized in that, include: The product includes a magnetic conductive component, a winding coil, an air gap adjustment component, a heat conduction component, an insulation component, and a product base; the magnetic conductive component consists of a U-shaped magnetic core and an I-shaped magnetic core interlocking to form a closed magnetic circuit structure. The winding coil is disposed in the groove of the U-shaped magnetic core and is electrically isolated from the magnetic core by the insulating component; The thermal conductive component includes a thermally conductive silicone pad disposed at the bottom of the magnetic component, used to conduct heat from the magnetic core to the product base; The air gap adjustment assembly includes an air gap adjustment structure disposed on the contact surface between the I-shaped magnetic core and the U-shaped magnetic core; The product base is fixedly connected to the magnetic conductive component and the heat conductive component; The groove width of the U-shaped magnetic core is smaller than the cross-sectional width of the I-shaped magnetic core, and the insulating component covers at least the surface of the I-shaped magnetic core.

2. The UI-shaped differential inductor as described in claim 1, characterized in that: The winding coil has a multi-layer flat conductor structure and contains at least two pairs of winding groups.

3. The UI-shaped differential inductor as described in claim 1, characterized in that: The air gap adjustment structure includes a gap control layer disposed between the first magnetically conductive component and the second magnetically conductive component.

4. The UI-shaped differential inductor as described in claim 3, characterized in that: The gap control layer includes an air gap gasket.

5. The UI-shaped differential inductor as described in claim 4, characterized in that: The thickness of the air gap gasket is set in an inverse relationship with the magnetic saturation parameter of the I-shaped magnetic core.

6. The UI-shaped differential inductor as described in claim 1, characterized in that: The insulating component includes an insulating skeleton molded from engineering plastic, the inner wall of which has a stepped anti-displacement structure.

7. The UI-shaped differential inductor as described in claim 1, characterized in that: The thermal conductivity of the thermally conductive silicone pad is in the range of 1.2-3.5 W / m·K, and the contact area with the bottom of the U-shaped magnetic core accounts for no less than 80%.

8. The UI-shaped differential inductor as described in claim 1, characterized in that: The winding coil comprises multiple independent windings, which are arranged in parallel within the concave cavity.

9. The UI-shaped differential inductor according to claim 1, characterized in that: The thickness of the thermally conductive silicone pad ranges from 0.5 to 1.5 mm.

10. The UI-shaped differential inductor as described in claim 1, characterized in that: An insulating pad is provided between the bottom of the U-shaped magnetic core and the thermally conductive silicone pad to enhance electrical isolation and assist in heat conduction.

Images