Common mode inductance for reducing leakage inductance of can bus

Abstract

This invention discloses a common-mode inductor for reducing leakage inductance in CAN communication buses, relating to the field of common-mode inductor technology. The coil winding structure of this invention comprises four layers of coil windings arranged sequentially from the inside out. The first and second layers of coil windings have N turns at equal intervals and are wound perpendicularly to the closed-loop iron core at 90 degrees. The third and fourth layers of coil windings have M turns at equal intervals and are wound at 45 degrees to the closed-loop iron core. This invention, by combining 45-degree and 90-degree winding, achieves optimal magnetic field uniformity in the phase difference, allowing the magnetic fields generated by the windings to complement each other spatially, reducing leakage magnetic field phenomena caused by local magnetic field concentration. The opposite orientation of adjacent winding layers further optimizes the magnetic field distribution, enhances the coupling effect between windings, and further reduces leakage inductance.

Description

Technical Field

[0001] This invention belongs to the field of common-mode inductor technology, and in particular relates to a common-mode inductor that reduces leakage inductance in the CAN communication bus. Background Technology

[0002] In automotive and industrial circuits, the CAN communication protocol is widely used due to its high reliability. Among them, the common-mode inductor is a key component for suppressing interference, and its performance directly affects the communication quality.

[0003] Currently, the traditional method for common-mode inductors involves perpendicular winding of the coil to the winding post. This method results in significant leakage inductance. Common methods such as parallel winding with two wires or multi-layer arbitrary winding lead to poor coupling between the windings, causing a large amount of magnetic flux to leak into the surrounding space. In CAN bus applications, the additional differential-mode impedance generated by leakage inductance interferes with signal transmission, causing signal distortion and attenuation, severely affecting communication stability. Especially in high-speed communication and complex electromagnetic environments, signal interference caused by leakage inductance becomes increasingly apparent. Existing common-mode inductor coil winding structures are insufficient to meet the high reliability and stability requirements of CAN communication in the automotive and industrial sectors. Therefore, to address these issues, this solution proposes a common-mode inductor that reduces leakage inductance in the CAN communication bus. Utility Model Content

[0004] This invention provides a common-mode inductor for reducing leakage inductance in CAN communication buses. The common-mode inductor consists of four layers of coil windings. The first and second layers are wound perpendicularly at 90 degrees, while the third and fourth layers are wound at 45-degree angles. Each layer has a concentric layered winding layout, and the first and second layers have more turns than the third and fourth layers. This optimizes coupling between winding groups, reduces leakage flux caused by differences in conductors, and the staggered winding sequence of the four layers ensures a more uniform magnetic field distribution, comprehensively reducing leakage inductance and improving signal transmission quality in practical CAN common-mode inductors. The combination of 45-degree and 90-degree windings achieves optimal magnetic field uniformity for phase differences, allowing the magnetic fields generated by the windings to complement each other spatially, resulting in a more uniform overall magnetic field distribution and reducing leakage flux caused by localized magnetic field concentration. Furthermore, the opposite orientation of adjacent winding layers further optimizes the magnetic field distribution, enhances coupling between windings, and further reduces leakage inductance. In summary, this invention solves the problems in the prior art.

[0005] To solve the above-mentioned technical problems, this utility model is achieved through the following technical solution:

[0006] This utility model provides a common-mode inductor for reducing leakage inductance in a CAN communication bus, comprising a closed-loop iron core and a welding pin disposed at one end of the closed-loop iron core, wherein the closed-loop iron core has a coil winding structure with a concentric layered winding layout symmetrically disposed on both sides.

[0007] The coil winding structure consists of four layers from the inside out: a first layer of coil winding, a second layer of coil winding, a third layer of coil winding, and a fourth layer of coil winding.

[0008] The first and second layer coil windings are both provided with N turns at equal intervals and are wound perpendicularly to the closed-loop iron core at 90 degrees. The first and second layer coil windings provide 55-65% of the inductance.

[0009] The third and fourth layer coil windings are both provided with M turns at equal intervals and are wound at a 45-degree angle with the closed-loop iron core. The third and fourth layer coil windings provide 35-45% of the inductance.

[0010] Furthermore, N is greater than M.

[0011] Furthermore, the third layer of coil windings and the fourth layer of coil windings are wound in opposite directions and cross each other.

[0012] Furthermore, the starting winding positions of the first layer coil winding, the second layer coil winding, the third layer coil winding, and the fourth layer coil winding on the closed-loop iron core are staggered.

[0013] Furthermore, the winding directions between the first layer coil winding and the second layer coil winding, between the second layer coil winding and the third layer coil winding, and between the third layer coil winding and the fourth layer coil winding are opposite.

[0014] The present invention has the following advantages over the prior art:

[0015] (1) The common mode inductor is composed of four layers of coil windings. The first and second layers are wound at a 90-degree angle, and the third and fourth layers are wound at a 45-degree angle. Each layer is a concentric layered winding layout. The number of turns of the first and second layers is greater than that of the third and fourth layers. This can optimize the coupling between the winding groups, reduce leakage magnetic field caused by differences in wires, and the four-layer staggered winding sequence can make the magnetic field distribution more uniform, reduce leakage inductance in all directions, and improve the signal transmission quality of the CAN common mode inductor in the actual circuit.

[0016] (2) By combining 45-degree winding and 90-degree winding, the phase difference can achieve the best magnetic field uniformity, so that the magnetic fields generated by the windings complement each other in space, the overall magnetic field distribution is more uniform, and the leakage magnetic phenomenon caused by local magnetic field concentration is reduced.

[0017] (3) The winding directions of adjacent layers are set in opposite directions, which can further optimize the magnetic field distribution, enhance the coupling effect between windings, and further reduce leakage inductance.

[0018] Of course, any product implementing this utility model does not necessarily need to achieve all of the advantages described above at the same time. Attached Figure Description

[0019] To more clearly illustrate the technical solutions of the embodiments of this utility model, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 This is a schematic diagram of a common-mode inductor structure for reducing leakage inductance in a CAN communication bus according to the present invention.

[0021] Figure 2 A schematic diagram of a structure in which the coil winding and the closed-loop iron core are wound at a 45-degree angle;

[0022] The attached diagram lists the components represented by each number as follows:

[0023] 1-Closed-loop iron core, 11-Fourth layer coil winding, 12-Third layer coil winding, 13-First layer coil winding, 14-Second layer coil winding, 15-Welding pin. Detailed Implementation

[0024] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of the present utility model.

[0025] In the description of this utility model, it should be understood that the terms "one end", "both sides", "concentric", "symmetrical", "spacing", "interlacing", etc., which indicate orientation or positional relationship, are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the components or elements referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model.

[0026] Please see Figure 1-2 As shown, this utility model discloses a common-mode inductor for reducing leakage inductance in a CAN communication bus, comprising a closed-loop iron core 1 and a welding pin 15 disposed at one end of the closed-loop iron core 1. The closed-loop iron core 1 has concentrically layered coil winding structures symmetrically arranged on both sides. The above structure is the same as the existing common-mode inductor structure, with the following differences and innovations:

[0027] The coil winding structure consists of four layers from the inside out: a first layer of coil winding 13, a second layer of coil winding 14, a third layer of coil winding 12, and a fourth layer of coil winding 11.

[0028] The first layer of coil winding 13 and the second layer of coil winding 14 are both provided with N turns at equal intervals, and are wound perpendicular to the closed ring iron core 1 at 90 degrees. The first layer of coil winding 13 and the second layer of coil winding 14 provide 55-65% of the inductance.

[0029] The third layer coil winding 12 and the fourth layer coil winding 11 are both provided with M turns at equal intervals, and are wound at a 45-degree angle with the closed ring iron core 1. The third layer coil winding 12 and the fourth layer coil winding 11 provide 35-45% of the inductance.

[0030] Where N is greater than M.

[0031] The third layer of coil winding 12 and the fourth layer of coil winding 11 are wound in opposite directions and cross each other.

[0032] The starting winding positions of the first layer coil winding 13, the second layer coil winding 14, the third layer coil winding 12, and the fourth layer coil winding 11 on the closed-loop iron core 1 are staggered.

[0033] The winding directions between the first layer coil winding 13 and the second layer coil winding 14, between the second layer coil winding 14 and the third layer coil winding 12, and between the third layer coil winding 12 and the fourth layer coil winding 11 are opposite.

[0034] This scheme adopts a concentric layered winding layout, dividing the magnetic core winding area radially from the inside to the outside into multiple layers of concentric windings. The number of turns and wire diameter of each layer of windings are optimized according to the magnetic field distribution inside the magnetic core. The windings adopt an interleaved winding sequence, with the starting winding positions of adjacent layers of windings staggered by a certain angle to make the magnetic field distribution more uniform and reduce leakage inductance. During the winding process, a closed-loop feedback system is used to monitor and adjust the winding tension in real time to ensure that the wires are tightly arranged and reduce leakage magnetic field caused by loose wires.

[0035] Based on the current density and magnetic field strength at different locations of the magnetic core, high permeability and low resistance wires are used in areas with high current density and strong magnetic field to optimize the distribution of wires in each layer of windings. After the winding is completed, the inductor is magnetically shielded as a whole, and high permeability material is used to wrap the inductor to further suppress leakage inductance to the external space.

[0036] In this specific embodiment:

[0037] (1) Adopting a concentric layered winding layout:

[0038] Zone division and winding design: Based on the basic inductance formula L=μN2 A / l, where L is the inductance, (mu) is the permeability, N is the number of turns, A is the cross-sectional area of ​​the magnetic core, and l is the magnetic circuit length), precisely divides the magnetic core winding area radially from the inside to the outside into four concentric windings; the inner two layers (first layer coil winding 13, second layer coil winding 14) bear approximately 60% of the inductance, and the outer two layers (third layer coil winding 12, fourth layer coil winding 11) bear 40%. Taking a 51μH inductor as an example, each inner layer has 10 turns (N=10), and each outer layer has 7 turns (M=7), with the total number of turns controlled between 34 and 36. The wire diameter of the first layer coil winding 13, the second layer coil winding 14, the third layer coil winding 12, and the fourth layer coil winding 11 is 0.05mm. The closed-loop iron core 1, i.e., the winding post, has a length of L: 0.9mm, a width of W: 2mm, and a circumference of 5.8mm.

[0039] (2) Interleaved winding sequence:

[0040] Winding start position setting: When winding adjacent layers, the inner layer winding starts from the horizontal right side of the core, and the first and second layers are wound at a perpendicular 90-degree angle; that is, the third and fourth layers. The adjacent outer layer winding starts at a 45° angle to the horizontal right side. The angle parameters are optimized and calculated using finite element simulation (such as Ansys Maxwell). A 45° reverse rotation reduces leakage inductance by 42% and increases the coupling coefficient by 28%. Actual experimental results show that a 45° reverse rotation reduces leakage inductance by 33% and increases the coupling coefficient by 22%. The configuration is determined in combination with parameters such as core size and number of winding layers. For example, for a toroidal core, a 45° phase difference usually provides the best magnetic field uniformity. This cross-setting allows the magnetic fields generated by the windings to complement each other in space, making the overall magnetic field distribution more uniform and reducing leakage magnetic field caused by local magnetic field concentration.

[0041] 45-degree winding: The winding is at a 45-degree angle to the core axis. When current flows in the winding, the electric field generated is relatively tilted around the core. Due to the tilt of the winding, the electric field has certain components in both the axial and radial directions of the core, making the distribution of electric field intensity on the core surface relatively uneven. Near the beginning and end of the winding, the electric field intensity may change significantly.

[0042] 90-degree winding: The winding is perpendicular to the core axis, and the electric field generated by the current is mainly concentrated in the radial direction of the core, with a smaller axial electric field component. Therefore, the electric field intensity is relatively uniformly distributed along the circumference of the core, but there are significant changes in electric field intensity at both ends of the core, exhibiting a strong edge effect.

[0043] Through the above implementation, 100 sets of data test tables were obtained:

[0044] Verification methods Parameter combination Leakage inductance reduction rate Coupling coefficient improvement Ansys Maxwell calculations 45° reverse 42％ 28％ Actual 100 sets of data 45° reverse Arithmetic mean 33% Arithmetic mean 22%

[0045] Table 1: Coupling Coefficient and Leakage Inductance Detection Table

[0046] As shown in Table 1 above, by using 45-degree reverse winding and calculating and comparing 100 sets of data, compared with the existing vertical winding, leakage inductance can be reduced by an average of 33% and coupling coefficient can be increased by an average of 22%.

[0047] Winding direction adjustment: In addition to crossing the starting position, the winding directions of adjacent layers can also be set to opposite directions. For example, the inner layer is wound clockwise and the outer layer is wound counterclockwise, which further optimizes the magnetic field distribution, enhances the coupling effect between windings, and reduces leakage inductance.

[0048]

[0049] Table 2: Comparison Table of Winding Angles

[0050] As shown in Table 2 above, the first and second layers are wound at 90 degrees, and the third and fourth layers are wound at 45 degrees. Under the conditions of 1MHz, 1V test level, short-circuiting one set of coils, and testing the other set of coils with a precision LCR instrument, compared with the existing four-layer vertical winding, the leakage inductance can be greatly reduced by about 25% or more.

[0051] The common-mode inductor in this design consists of four layers of coil windings. The first and second layers are wound perpendicularly at 90 degrees, while the third and fourth layers are wound at 45-degree angles. Each layer has a concentric layered winding layout, and the first and second layers have more turns than the third and fourth layers. This optimizes the coupling between the winding groups, reduces leakage flux caused by differences in conductors, and the staggered winding sequence of the four layers ensures a more uniform magnetic field distribution, reducing leakage inductance from all directions and improving the signal transmission quality of the CAN common-mode inductor in actual circuit applications. The combination of 45-degree and 90-degree windings achieves optimal magnetic field uniformity in the phase difference, allowing the magnetic fields generated by the windings to complement each other spatially, resulting in a more uniform overall magnetic field distribution and reducing leakage flux caused by localized magnetic field concentration. The opposite orientation of adjacent winding layers further optimizes the magnetic field distribution, enhances the coupling effect between windings, and further reduces leakage inductance.

[0052] The preferred embodiments of this utility model disclosed above are merely illustrative of the present utility model. These preferred embodiments do not exhaustively describe all details, nor do they limit the utility model to the specific implementations described. Clearly, many modifications and variations can be made based on the content of this specification. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of this utility model, thereby enabling those skilled in the art to better understand and utilize it. This utility model is limited only by the claims and their full scope and equivalents.

Claims

1. A common-mode inductor for reducing leakage inductance in a CAN communication bus, comprising a closed-loop iron core (1) and a solder pin (15) disposed at one end of the closed-loop iron core (1), wherein the closed-loop iron core (1) has a coil winding structure with a concentric layered winding layout symmetrically arranged on both sides, characterized in that: The coil winding structure consists of four layers from the inside out: a first layer of coil winding (13), a second layer of coil winding (14), a third layer of coil winding (12), and a fourth layer of coil winding (11). The first layer coil winding (13) and the second layer coil winding (14) are provided with N turns at equal intervals and are wound perpendicularly to the closed ring iron core (1) at 90 degrees. The first layer coil winding (13) and the second layer coil winding (14) provide 55-65% of the inductance. The third layer coil winding (12) and the fourth layer coil winding (11) are both provided with M turns at equal intervals, and are wound at 45 degrees with the closed ring core (1). The third layer coil winding (12) and the fourth layer coil winding (11) provide 35-45% of the inductance.

2. A common mode choke for reducing leakage inductance of a CAN bus according to claim 1, characterized in that The N is greater than M.

3. The common mode choke for reducing leakage inductance of a CAN bus of claim 1, wherein, The third layer coil winding (12) and the fourth layer coil winding (11) are wound in opposite directions and cross each other.

4. The common mode choke for reducing leakage inductance of a CAN bus of claim 1, wherein, The starting winding positions of the first layer coil winding (13), the second layer coil winding (14), the third layer coil winding (12) and the fourth layer coil winding (11) on the closed ring core (1) are staggered.

5. The common mode choke for reducing leakage inductance of a CAN bus of claim 1, wherein, The winding directions between the first layer coil winding (13) and the second layer coil winding (14), between the second layer coil winding (14) and the third layer coil winding (12), and between the third layer coil winding (12) and the fourth layer coil winding (11) are opposite.

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