Differential common mode integrated inductor

Abstract

The application discloses a differential common mode integrated inductor, and relates to the technical field of electrical components.The inductor comprises a magnetic core assembly, four coils, a base and a protective plate.The magnetic core assembly comprises a main magnetic core and a magnetic conductive isolation part, and the magnetic circuit of the magnetic core assembly is in a frame shape.The magnetic conductive isolation part comprises a magnetic conductive magnetic core and an insulating isolation piece, the magnetic conductive magnetic core is fixedly connected with the main magnetic core through the insulating isolation piece, and the magnetic permeability of the main magnetic core is higher than that of the magnetic conductive magnetic core.The four coils are electrically isolated and arranged in corresponding winding subareas.When common mode current flows, the common mode magnetic flux mainly flows through the main magnetic core with high magnetic permeability, thereby realizing high inductance common mode filtering; when differential mode current flows, at least part of the differential mode magnetic flux concentrates through the magnetic conductive magnetic core with low magnetic permeability, thereby forming a high magnetic resistance path, and the high saturation magnetic flux density characteristic of the magnetic conductive magnetic core is utilized to avoid saturation, thereby improving the differential mode inductance.On the basis of ensuring high magnetic permeability common mode filtering, the differential mode inductance and the differential mode filtering effect are greatly improved.

Description

Technical Field

[0001] This invention relates to the field of electrical component technology, and in particular to a differential and common-mode integrated inductor. Background Technology

[0002] With the rapid development of power electronics technologies such as new energy vehicles, industrial frequency conversion, precision industrial control, and high-frequency switching power supplies, the power density and switching frequency of equipment are constantly increasing, making electromagnetic interference (EMI) problems increasingly prominent. Differential-mode interference and common-mode interference are the two most important sources of EMI in circuits, and their effective suppression is a key aspect of ensuring the electromagnetic compatibility and operational stability of equipment.

[0003] Specifically, common-mode interference manifests as a noise current in the same direction between the phase line and ground, requiring the filter inductor to provide extremely high common-mode impedance over a wide frequency range. Therefore, the common-mode core needs to possess extremely high initial permeability (μi) to achieve a sufficiently large inductance with a small number of turns, while also requiring low core loss and excellent high-frequency characteristics. Currently, nanocrystalline soft magnetic alloys (such as iron-based nanocrystalline ribbons) have become the preferred core material for high-performance common-mode inductors due to their permeability reaching tens of thousands, high saturation flux density (Bs), and significantly lower high-frequency losses compared to traditional ferrites.

[0004] Differential-mode interference manifests as reverse noise current between phase lines, typically accompanied by a large DC bias or a low-frequency, high-current component. Differential-mode inductors need to maintain their inductance without decaying under high-current conditions, which places entirely different demands on the magnetic core: it needs to have low permeability to withstand larger DC biases without easily saturating, while also requiring extremely high saturation flux density (Bs) and a distributed air gap structure to ensure uniform flux distribution within the material, avoiding a sudden drop in inductance due to local saturation.

[0005] However, the two types of magnetic performance requirements mentioned above are inherently contradictory in physical terms and difficult to reconcile with a single magnetic core material: high permeability materials (such as nanocrystals) are prone to entering the saturation region under DC bias, leading to a sharp decrease in differential-mode inductance; while low permeability materials with distributed air gaps (such as iron-silicon magnetic powder cores), although possessing strong anti-saturation capabilities, are unable to provide the high inductance required for common-mode filtering within a limited volume. Therefore, a single magnetic core material cannot simultaneously meet the dual requirements of high common-mode inductance and differential-mode anti-saturation.

[0006] Currently, the main filtering schemes for the above-mentioned interference include the following technical approaches: Firstly, the separate combination of independent differential-mode inductors and common-mode inductors requires the placement of two types of components on the circuit board, resulting in a large overall footprint, cumbersome wiring, and numerous assembly steps, which severely restricts the development of power equipment towards miniaturization and high integration. At the same time, the separate structure results in longer circuit traces, larger parasitic parameters, and a tendency to generate resonance and signal attenuation under high-frequency operating conditions, leading to a significant reduction in filtering efficiency.

[0007] Secondly, a single-core integrated scheme is adopted, attempting to simultaneously wind differential-mode and common-mode coils on the same core. For example, an air gap is added to the nanocrystalline core to accommodate differential-mode bias capability, or the number of turns is increased on the iron-silicon core to improve common-mode inductance. However, such schemes are essentially "forcing the feet to fit the shoes": adding an air gap to the nanocrystalline core significantly reduces its effective permeability, weakening the common-mode filtering effect, and leakage flux and localized heating are easily generated at the concentrated air gap; while relying on the iron-silicon core to provide common-mode inductance requires a large number of turns or a large volume to meet the filtering requirements due to its low permeability, which runs counter to the goal of miniaturization.

[0008] Furthermore, in multi-channel power supply equipment (such as a four-channel synchronous power supply system), the above contradictions are further aggravated: multi-channel integration requires the magnetic core to form multiple independent and symmetrical filter circuits within a limited space. If a single material scheme is used, the magnetic flux coupling interference, local magnetic saturation, and parameter drift problems between the circuits will become more prominent. The existing structure is difficult to balance the four-channel symmetry and differential common-mode dual filtering performance. Summary of the Invention

[0009] The purpose of this invention is to provide a differential-mode and common-mode integrated inductor to solve the problems existing in the prior art, thereby improving the differential-mode inductance and differential-mode filtering effect while ensuring high permeability common-mode filtering.

[0010] To achieve the above objectives, the present invention provides the following solution: This invention provides a differential and common-mode integrated inductor, comprising: A magnetic core assembly includes a main magnetic core and a magnetically conductive isolation section. The main magnetic core has a closed magnetic circuit and is frame-shaped. The magnetically conductive isolation section includes a magnetically conductive core and an insulating isolation member. The magnetically conductive core and the main magnetic core are respectively fixedly connected to the insulating isolation member. The insulating isolation member is located between the main magnetic core and the magnetically conductive core, and the insulating isolation member divides the inner cavity of the main magnetic core into four independent winding sections. The permeability of the main magnetic core is higher than that of the magnetically conductive core. Four coils, each corresponding to one of the winding sections, are electrically isolated and wound on the main magnetic core, with each coil located within its corresponding winding section. When differential mode current flows through the four coils, at least a portion of the differential mode magnetic flux is forced to concentrate through the magnetic core, thereby forming a differential mode magnetic flux path with high magnetic resistance; while when common mode current flows through the four coils, the common mode magnetic flux mainly flows through the main magnetic core.

[0011] Preferably, the main magnetic core is formed by winding nanocrystalline ribbon, and the surface of the main magnetic core is coated with an insulating layer.

[0012] Preferably, the magnetic core is an iron-silicon magnetic core.

[0013] Preferably, the insulating isolator is provided with a first receiving area corresponding to each of the coils, and the insulating isolator is also provided with a second receiving area for accommodating a portion of the magnetic core.

[0014] Preferably, the insulating isolator is provided with a cross-shaped isolation plate, which is located in the inner cavity of the main magnetic core.

[0015] Preferably, it also includes a base for supporting the magnetic core assembly, the base having holes through which the leads of the coil pass.

[0016] Preferably, the base is provided with lead wires that correspond one-to-one with the pins of all the coils, with one end of the lead wire connected to the corresponding pin and the other end extending out of the base.

[0017] Preferably, it also includes a protective plate, which is detachably connected to the side of the base away from the magnetic core assembly, and the protective plate is used to cover all the holes.

[0018] Preferably, the lead wire is made of copper busbar.

[0019] Preferably, the four coils are of two specifications, with two coils of each specification, and the two coils of the same specification are symmetrically distributed on the main magnetic core.

[0020] The present invention achieves the following technical effects compared to the prior art: The integrated differential and common-mode inductor of this invention clearly divides the magnetic core assembly into a main magnetic core with high permeability and a guide magnetic core with low permeability. The main magnetic core is formed by winding nanocrystalline ribbon, which, with its extremely high initial permeability, provides a complete magnetic circuit with low magnetic reluctance for the common-mode flux when common-mode current flows through the four coils, thus ensuring the high inductance required for common-mode filtering. The guide magnetic core is made of iron-silicon, which has a high saturation flux density (Bs) and a natural distributed air gap. When differential-mode current flows through the four coils, it forces at least a portion of the differential-mode flux to concentrate through the guide magnetic core, forming a high-resistance differential-mode flux path. Under high-resistance path conditions, the iron-silicon material effectively resists DC bias due to its high Bs characteristics, avoiding local saturation, thereby significantly improving differential-mode inductance and differential-mode filtering effect while ensuring high permeability common-mode filtering. Attached Figure Description

[0021] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0022] Figure 1 This is a schematic diagram of the differential and common-mode integrated inductor of the present invention; Figure 2 This is a partial structural schematic diagram of the differential and common-mode integrated inductor of the present invention; Figure 3 This is a schematic diagram of the base structure in the differential and common mode integrated inductor of the present invention; In the diagram: 1. Main magnetic core; 2. Insulating isolation component; 201. Cross isolation plate; 3. Coil; 301. Pin; 4. Magnetic core; 5. Base; 501. Hole; 6. Lead wire; 7. Protective plate. Detailed Implementation

[0023] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0024] The purpose of this invention is to provide a differential-mode and common-mode integrated inductor to solve the problems existing in the prior art, thereby improving the differential-mode inductance and differential-mode filtering effect while ensuring high permeability common-mode filtering.

[0025] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0026] like Figures 1 to 3 As shown, this embodiment provides a differential and common-mode integrated inductor, including: The magnetic core assembly includes a main magnetic core 1 and a magnetically conductive isolation section. The main magnetic core 1 has a closed magnetic circuit and is frame-shaped. The magnetically conductive isolation section includes a magnetically conductive core 4 and an insulating isolation component 2. The magnetically conductive core 4 and the main magnetic core 1 are respectively fixedly connected to the insulating isolation component 2. The insulating isolation component 2 is located between the main magnetic core 1 and the magnetically conductive core 4, and the insulating isolation component 2 divides the inner cavity of the main magnetic core 1 into four independent winding sections. The permeability of the main magnetic core 1 is higher than that of the magnetically conductive core 4. Four coils 3, each corresponding to a winding section, are electrically isolated and wound on the main magnetic core 1, with each coil 3 located within its corresponding winding section. When differential mode current flows through the four coils 3, at least part of the differential mode magnetic flux is forced to concentrate through the magnetic core 4, thereby forming a differential mode magnetic flux path with high magnetic resistance; while when common mode current flows through the four coils 3, the common mode magnetic flux mainly flows through the main magnetic core 1.

[0027] In the optional embodiments of this example, the main magnetic core 1 is preferably formed by winding nanocrystalline strip, and the surface of the main magnetic core 1 is coated with an insulating layer. The insulating layer coated on the surface of the main magnetic core 1 forms a dense insulating film on the surface of each turn of the strip, electrically isolating each layer of the strip, forcing the eddy current to be confined to the thickness of a single layer of strip, thereby significantly reducing high-frequency eddy current loss.

[0028] In the optional schemes of this embodiment, the preferred option is that the magnetic core 4 is an iron-silicon magnetic core.

[0029] The magnetic core assembly in this embodiment includes a main magnetic core 1 with high permeability and a magnetic core 4 with low permeability. The main magnetic core 1 is formed by winding nanocrystalline ribbon. Due to its extremely high initial permeability, it provides a complete magnetic circuit with low magnetic reluctance for the common-mode flux when common-mode current flows through the four coils 3, thus ensuring the high inductance required for common-mode filtering. The magnetic core 4 is made of iron-silicon, possessing high saturation flux density (Bs) and a natural distributed air gap. When differential-mode current flows through the four coils 3, it forces at least a portion of the differential-mode flux to concentrate through the magnetic core 4, forming a high-resistance differential-mode flux path. Under high-resistance path conditions, the iron-silicon material effectively resists DC bias due to its high Bs characteristic, avoiding local saturation. Therefore, while ensuring high permeability common-mode filtering, it significantly improves differential-mode inductance and differential-mode filtering effect.

[0030] In the optional embodiments of this example, a preferred embodiment is provided with a first receiving area corresponding to the coil 3 on the insulating isolator 2, and a second receiving area on the insulating isolator 2 to receive a portion of the magnetic core 4. On the one hand, the insulating isolator 2 physically connects and separates the main magnetic core 1 and the magnetic core 4, preventing complete interconnection of their magnetic circuits. This ensures that the common-mode magnetic flux is mainly confined to the high-permeability main magnetic core 1, while the differential-mode magnetic flux is guided and concentrated through the magnetic core 4. On the other hand, the first and second receiving areas on the insulating isolator 2 respectively receive the coil 3 and the magnetic core 4, achieving precise positioning and multiple insulation isolation within the core assembly. This eliminates electromagnetic crosstalk between the four circuits, ensures uniform coupling of the four magnetic fluxes, and avoids local magnetic saturation and inductance parameter drift.

[0031] In the optional embodiments of this example, a preferred embodiment is that the insulating isolator 2 is provided with a cross-shaped isolation plate 201, which is located inside the cavity of the main magnetic core 1. The cross-shaped isolation plate 201 physically divides the cavity of the main magnetic core 1 into four independent winding sections, with the four coils 3 wound one-to-one in each section and electrically isolated. This structure allows a single device to replace the traditional combination of four independent differential-mode and common-mode inductors, significantly reducing the overall space occupied and wiring length, lowering parasitic parameters, effectively avoiding resonance and signal attenuation problems under high-frequency operating conditions, and perfectly meeting the miniaturization and high integration design requirements of four-way synchronous power supply equipment.

[0032] In the optional embodiments of this example, a more preferred option is to include a base 5, which is used to support the magnetic core assembly. The base 5 is provided with holes 501 through which the pins 301 of the coil 3 pass.

[0033] More preferably, the base 5 is provided with lead wires 6 that correspond one-to-one with the pins 301 of all the coils 3. One end of the lead wire 6 is connected to the corresponding pin 301, and the other end extends out of the base 5.

[0034] More preferably, it also includes a protective plate 7, which is detachably connected to the side of the base 5 away from the magnetic core assembly, and the protective plate 7 is used to cover all holes 501.

[0035] The base 5 not only supports the magnetic core assembly, but also has holes 501 for the coil 3 pins 301 to pass through, and has lead wires 6 (preferably copper busbars) corresponding to the pins 301 one by one inside, which greatly improves the flexibility of pin 301 connection and lead-out; the protective plate 7 is detachably connected to the side of the base 5 away from the magnetic core assembly, which can fully cover all holes 501, effectively isolate the bottom solder joints from the safety distance of the device below, and improve the electrical safety performance and structural stability of the device under harsh industrial conditions.

[0036] In the optional schemes of this embodiment, it is more preferred that the lead wire 6 is a copper busbar.

[0037] In the optional scheme of this embodiment, a preferred embodiment is that the four coils 3 are divided into two specifications, with two coils of each specification, and the two coils 3 of the same specification are symmetrically distributed on the main magnetic core 1. This design ensures a high degree of matching of the electrical parameters of the four independent filter circuits, effectively suppressing filtering performance deviations caused by winding differences, and guaranteeing the consistency and reliability of the filtering effect of each circuit in multi-power supply scenarios.

[0038] The specific working principle of the differential and common-mode integrated inductor in this embodiment is as follows: (1) Common-mode interference: When common-mode interference is generated in the four-way synchronous power supply system of the external circuit, the noise current flows into the four coils 3 in the same direction and with the same magnitude. At this time, the common-mode magnetic flux generated by the four coils 3 is in the same direction, and the magnetic flux is mainly confined to the main magnetic core 1 with high permeability. Since the main magnetic core 1 is formed by winding nanocrystalline strip, it has extremely high initial permeability and can provide a complete closed magnetic circuit with extremely low magnetic resistance for the common-mode current, thereby inducing extremely high common-mode inductance on the four coils 3, generating a strong choking effect on the common-mode interference current, and realizing efficient common-mode filtering. At the same time, the insulating layer sprayed on the surface of the main magnetic core 1 effectively blocks the eddy current path between the nanocrystalline strip layers, greatly reducing the eddy current loss under high-frequency conditions and ensuring the stability of common-mode filtering in a wide frequency range.

[0039] (2) Differential-mode interference: When differential-mode interference exists in the circuit (accompanied by large current DC bias), the noise current flows through the four coils 3 in opposite directions between the phase lines; at this time, the directions of the differential-mode magnetic flux generated by the four coils 3 are mutually opposed; since the permeability of the main magnetic core 1 is extremely high, if all the differential-mode magnetic flux flows through the main magnetic core 1, it will easily lead to core saturation, causing the differential-mode inductance to drop sharply; in this embodiment, the flow path of the differential-mode magnetic flux is forcibly redistributed by the cross isolation plate 201 on the insulating isolation component 2 and the magnetically conductive isolation part: the cross isolation plate 201 physically divides the inner cavity of the main magnetic core 1 into four independent winding sections, forcing the magnetic flux generated by the coils 3 to be limited within the sections; at the same time, the insulating isolation component 2 is located between the main magnetic core 1 and the magnetically conductive core 4, which will The two magnetic circuits are isolated. Under differential mode current excitation, due to the high permeability of the main magnetic core 1, some differential mode flux attempts to flow through the main magnetic core 1, but the barrier of the insulating isolator 2 forces at least some differential mode flux to concentrate through the magnetic core 4. The magnetic core 4 is made of iron-silicon, and its permeability is much lower than that of the main magnetic core 1. Therefore, this differential mode flux path through the magnetic core 4 exhibits high magnetoresistance characteristics. It is this high magnetoresistance path that effectively suppresses the sharp rise in magnetic flux density (B). At the same time, the iron-silicon material has extremely high saturation magnetic flux density (Bs) and a natural distributed air gap. Even under high current DC bias, it can withstand high magnetic field strength without easily saturating due to its high Bs characteristics, thereby maintaining the stability of differential mode inductance and significantly improving the differential mode filtering effect.

[0040] While the magnetic circuit operates efficiently, the base 5 supports the magnetic core assembly. The pins 301 of the coil 3 pass through the holes 501 on the base 5 and connect to the copper busbars inside the base 5, enabling flexible pin connection. The protective plate 7 covers the holes 501, isolating the bottom solder joints from the safety distance of the components below. The insulating isolator 2 not only guides the magnetic circuit, but its first and second receiving areas also fix the coil 3 and the magnetic core 4, respectively, ensuring the long-term stability of the overall structure under vibration and high / low temperature conditions.

[0041] Specific examples have been used to illustrate the principles and implementation methods of this invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of this invention. Furthermore, those skilled in the art will recognize that, based on the ideas of this invention, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of this invention.

Claims

1. A differential and common-mode integrated inductor, characterized in that, include: A magnetic core assembly includes a main magnetic core and a magnetically conductive isolation section. The main magnetic core has a closed magnetic circuit and is frame-shaped. The magnetically conductive isolation section includes a magnetically conductive core and an insulating isolation member. The magnetically conductive core and the main magnetic core are respectively fixedly connected to the insulating isolation member. The insulating isolation member is located between the main magnetic core and the magnetically conductive core, and the insulating isolation member divides the inner cavity of the main magnetic core into four independent winding sections. The permeability of the main magnetic core is higher than that of the magnetically conductive core. Four coils, each corresponding to one of the winding sections, are electrically isolated and wound on the main magnetic core, with each coil located within its corresponding winding section. When differential mode current flows through the four coils, at least a portion of the differential mode magnetic flux is forced to concentrate through the magnetic core, thereby forming a differential mode magnetic flux path with high magnetic resistance; while when common mode current flows through the four coils, the common mode magnetic flux mainly flows through the main magnetic core.

2. The differential and common-mode integrated inductor according to claim 1, characterized in that: The main magnetic core is formed by winding nanocrystalline ribbon, and the surface of the main magnetic core is coated with an insulating layer.

3. The differential and common-mode integrated inductor according to claim 1, characterized in that: The magnetic core is made of iron-silicon.

4. The differential and common-mode integrated inductor according to claim 1, characterized in that: The insulating isolator is provided with a first receiving area corresponding to each of the coils, and the insulating isolator is also provided with a second receiving area for accommodating part of the magnetic core.

5. The differential and common-mode integrated inductor according to claim 1, characterized in that: The insulating isolator is provided with a cross-shaped isolation plate, which is located in the inner cavity of the main magnetic core.

6. The differential and common-mode integrated inductor according to claim 1, characterized in that: It also includes a base for supporting the magnetic core assembly, the base having holes through which the leads of the coil pass.

7. The differential and common-mode integrated inductor according to claim 6, characterized in that: The base is provided with lead wires that correspond one-to-one with the pins of all the coils. One end of each lead wire is connected to the corresponding pin, and the other end extends out of the base.

8. The differential and common-mode integrated inductor according to claim 7, characterized in that: It also includes a protective plate, which is detachably connected to the side of the base away from the magnetic core assembly, and the protective plate is used to cover all the holes.

9. The differential and common-mode integrated inductor according to claim 7, characterized in that: The lead wires are made of copper busbars.

10. The differential and common-mode integrated inductor according to claim 1, characterized in that: The four coils are divided into two specifications, with two coils of each specification, and the two coils of the same specification are symmetrically distributed on the main magnetic core.

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