A method for optimizing the magnetic sensing characteristics of an island series variable cross-section micro-nano coil

Abstract

The application discloses a kind of island series variable cross-section micro-nano coil magnetic sensitive sensing characteristic optimization methods, including plane square spiral coil as design basis;According to the influence of internal eddy current of square spiral coil and coil resistance on the quality of coil, the quality of coil is improved by reducing the internal coil section and increasing the external coil section;Small spiral island is added around the coil;The magnetic field distribution and inductance value of different island number plane square spiral coil are analyzed and compared, and the final optimization design scheme of coil is determined.The island series variable cross-section micro-nano coil magnetic sensitive sensing characteristic optimization method reduces the internal section of coil to weaken the eddy current loss caused by the induced magnetic field perpendicular to the conductor generated by the coil;Increase the external section of coil to reduce the impedance loss caused by the excessive internal resistance of coil, connect the small spiral coil in the form of island in series into the plane coil, and further optimize the performance of plane coil by analyzing and optimizing the number of island.

Description

Technical Field

[0001] This invention relates to the field of planar coil technology for magnetic sensors, and more particularly to a method for optimizing the magnetic sensing characteristics of an islanded series-connected variable cross-section micro / nano coil. Background Technology

[0002] Magnetic sensors can convert changing magnetic field signals into electrical signals. Magnetic fields and related information exist extensively in nature and human society; the Earth itself is a large magnetic field. We are constantly surrounded by magnetic fields, therefore, detecting, collecting, storing, converting, and monitoring various magnetic fields and the information within them has become indispensable. To achieve these functions, magnetic sensors are essential. In today's information age, magnetic sensors have become a fundamental component of information technology and the information industry. Many types of magnetic sensors have been developed and are widely used in production, scientific research, and various aspects of social life.

[0003] In current measurement, magnetic sensors can be used to measure the magnetic field around the current, and then the excitation current can be calculated using relevant algorithms. For many years, Hall effect sensors have been used to measure current. With the research and development of magnetic sensors, sensors using planar coils as the main structure have gradually become more active in the market. Micro-nano magnetic coil sensors have become a hot research topic in recent years due to their small size, light weight, low power consumption, and excellent performance. As an important component of magnetic sensors, the planar coil determines the main performance indicators of some key circuit components. Therefore, optimizing the design of the planar coil is extremely important.

[0004] Design schemes for the overall shape of helical coils mainly include regular polygonal helical or concentric coils such as triangles, rectangles, pentagons, and hexagons; design schemes for the lead welding problem of planar coils mainly include irregular lead coils on the same side such as serpentine, flower-shaped, and mesh structures; and design schemes for coil spacing include irregular helical coils such as variable-pitch helical coils and eccentric helical coils.

[0005] The planar coils obtained by the above design schemes did not achieve good performance, mainly due to the low magnetic field strength generated after the coil is energized or the cancellation of the induced magnetic field. The improvement in inductance value compared with commonly used planar spiral coils was not significant. Summary of the Invention

[0006] The purpose of this section is to outline some aspects of embodiments of the present invention and to briefly describe some preferred embodiments. Simplifications or omissions may be made in this section, as well as in the abstract and title of this application, to avoid obscuring the purpose of these documents; however, such simplifications or omissions should not be construed as limiting the scope of the invention.

[0007] In view of the problems existing in the above-mentioned methods for optimizing the magnetic sensing characteristics of isolated series variable cross-section micro / nano coils, this invention is proposed.

[0008] Therefore, the purpose of this invention is to provide a method for optimizing the magnetic sensing characteristics of an islanded series-connected variable cross-section micro / nano coil, the purpose of which is to optimize the planar coil and improve its performance.

[0009] To solve the above-mentioned technical problems, the present invention provides the following technical solution: including using a planar square spiral coil as the design basis; based on the influence of the eddy current inside the square spiral coil and the external resistance of the coil on the coil quality, adopting the method of reducing the cross-section of the internal coil and increasing the cross-section of the external coil to improve the coil quality; adding small spiral islands around the coil; analyzing and comparing the magnetic field distribution and inductance value of planar square spiral coils with different numbers of islands, and determining the final optimized design scheme of the coil.

[0010] As a preferred embodiment of the method for optimizing the magnetic sensing characteristics of the islanded series variable cross-section micro / nano coils described in this invention, the islanded coils are regularly distributed outside the planar spiral coils and connected in series.

[0011] As a preferred embodiment of the method for optimizing the magnetic sensing characteristics of the islanded series variable cross-section micro / nano coil described in this invention, the leads at both ends of the islanded coil are connected by wires of the same material.

[0012] As a preferred embodiment of the method for optimizing the magnetic sensing characteristics of the isolated series-connected variable cross-section micro / nano coil described in this invention, the inductance value is calculated using the following formula after considering the self-inductance and mutual inductance of the spiral coil:

[0013]

[0014] Where: L is the coil inductance; μ0 is the vacuum conductivity, with a value of 4π × 10⁻⁷ H·m⁻¹; l is the total length of the coil; n is the number of coil turns; w is the width of the coil wire; t is the thickness of the wire; d + The average distance between parallel segments on the same side of the square is the positive mutual inductance constituent factor.

[0015] As a preferred embodiment of the method for optimizing the magnetic sensing characteristics of the islanded series variable cross-section micro / nano coil described in this invention, the average distance between parallel segments on the same side of the square, where the positive mutual inductance constituent factor is a factor, can be calculated by the following closed formula:

[0016]

[0017] Where, d + is the average distance between parallel segments on the same side of the square, representing the positive mutual inductance factor; w is the width of the coil conductor; n is the number of coil turns; and s is the spacing between adjacent coil conductors.

[0018] As a preferred embodiment of the method for optimizing the magnetic sensing characteristics of the islanded series variable cross-section micro / nano coil described in this invention, the relationship between the coil inductance L and the number of islands is set by the following formula:

[0019] L = L0 + N·L S

[0020] Where: L is the coil inductance; L0 is the coil inductance value without series islanding; L S is the inductance value of the islanded coil; N is the number of islands.

[0021] As a preferred embodiment of the method for optimizing the magnetic sensing characteristics of the islanded series variable cross-section micro / nano coil described in this invention, under the same conditions, when the preset inductance value is 10.4nH, the number of islands needs to be increased from 0 to 1; when the preset inductance value is 10.6nH, the number of islands needs to be increased from 1 to 2; when the preset inductance value is 10.8nH, the number of islands needs to be increased from 2 to 3; when the preset inductance value is 11.0nH, the number of islands needs to be increased from 3 to 4; and when the preset inductance value is 12.1nH, the number of islands needs to be increased from 4 to 8.

[0022] As a preferred embodiment of the method for optimizing the magnetic sensing characteristics of the islanded series variable cross-section micro / nano coil described in this invention, wherein: the analysis and comparison are performed by setting the material as copper and the remaining materials as air.

[0023] As a preferred embodiment of the method for optimizing the magnetic sensing characteristics of the islanded series variable cross-section micro / nano coil described in this invention, wherein: the analysis and comparison involves applying a 1A DC current excitation to the coil.

[0024] As a preferred embodiment of the method for optimizing the magnetic sensing characteristics of the islanded series variable cross-section micro / nano coil described in this invention, the islanded coil has a thickness of 5 μm, an inner coil side length of 60 μm, an outer coil side length of 80 μm, and a spacing of 10 μm.

[0025] The beneficial effects of this invention are as follows: Starting with an innovative coil structure, the concept of variable cross-section is introduced into the device structure design. The internal cross-section of the coil is reduced to weaken the eddy current loss caused by the induced magnetic field generated by the coil being perpendicular to the conductor. The external cross-section of the coil is increased to reduce the impedance loss caused by excessive internal resistance of the coil. Small spiral coils are connected in series with planar coils in the form of islands. The number of islands is optimized through formula analysis, which further optimizes the performance, magnetic field distribution and inductance of the planar coil. Attached Figure Description

[0026] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the description of 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. Wherein:

[0027] Figure 1 This is a schematic diagram illustrating the coil distance calculation in the method for optimizing the magnetic sensing characteristics of isolated series-connected variable cross-section micro / nano coils according to the present invention.

[0028] Figure 2 This is a schematic diagram of the magnetic field distribution of a coil with zero islands in the method for optimizing the magnetic sensing characteristics of islanded series variable cross-section micro / nano coils according to the present invention.

[0029] Figure 3 This is a schematic diagram of the magnetic field distribution of one islanded coil in the magnetic sensing characteristic optimization method of the islanded series variable cross-section micro / nano coil of the present invention.

[0030] Figure 4 This is a schematic diagram of the magnetic field distribution of two islanded coils in the method for optimizing the magnetic sensing characteristics of the islanded series variable cross-section micro / nano coils of the present invention.

[0031] Figure 5 This is a schematic diagram of the magnetic field distribution of three islanded coils in the method for optimizing the magnetic sensing characteristics of the islanded series variable cross-section micro / nano coils of the present invention.

[0032] Figure 6 This is a schematic diagram of the magnetic field distribution of four islanded coils in the magnetic sensing characteristic optimization method of the islanded series variable cross-section micro / nano coil of the present invention.

[0033] Figure 7 This is a schematic diagram of the magnetic field distribution of 8 islanded coils in the magnetic sensing characteristic optimization method of the islanded series variable cross-section micro / nano coil of the present invention.

[0034] Figure 8 This is a schematic diagram comparing the coil inductance values ​​of various numbers of islands in the optimization method for the magnetic sensing characteristics of the islanded series variable cross-section micro / nano coils of the present invention.

[0035] Figure 9 This is a schematic diagram of a planar spiral coil structure with eight small square spiral islands connected in series, which is the magnetic sensing characteristic optimization method of the islanded series variable cross-section micro / nano coil of the present invention.

[0036] Figure 10 This is a schematic diagram of the hexagonal coil structure of the method for optimizing the magnetic sensing characteristics of isolated series variable cross-section micro / nano coils according to the present invention.

[0037] Figure 11 This is a schematic diagram of the triangular coil structure of the method for optimizing the magnetic sensing characteristics of isolated series variable cross-section micro / nano coils according to the present invention.

[0038] Figure 12 This is a schematic diagram of the pentagonal coil structure of the method for optimizing the magnetic sensing characteristics of isolated series variable cross-section micro / nano coils according to the present invention.

[0039] Figure 13 This diagram illustrates a comparison between the inductance value of the optimized magnetic sensing characteristics method for the islanded series variable cross-section micro / nano coil of the present invention and the inductance value of existing shaped coils. Detailed Implementation

[0040] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0041] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and those skilled in the art can make similar extensions without departing from the spirit of the invention. Therefore, the invention is not limited to the specific embodiments disclosed below.

[0042] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The phrase "in one embodiment" appearing in different places in this specification does not necessarily refer to the same embodiment, nor is it a single or selective embodiment that is mutually exclusive with other embodiments.

[0043] Secondly, the present invention is described in detail with reference to the schematic diagrams. When detailing the embodiments of the present invention, for ease of explanation, the cross-sectional views illustrating the device structure may be partially enlarged, not according to the usual scale. Furthermore, the schematic diagrams are merely examples and should not limit the scope of protection of the present invention. In addition, actual fabrication should include three-dimensional spatial dimensions of length, width, and depth.

[0044] Example 1

[0045] Reference Figures 1-7This is the first embodiment of the present invention, which provides a method for optimizing the magnetic sensing characteristics of an islanded series-connected variable cross-section micro / nano coil.

[0046] This includes using a planar square spiral coil as the design basis; based on the influence of the internal eddy currents of the square spiral coil and the external resistance of the coil on the coil quality, adopting the method of reducing the internal coil cross-section and increasing the external coil cross-section to improve the coil quality; adding small spiral islands around the coil; analyzing and comparing the magnetic field distribution and inductance value of planar square spiral coils with different numbers of islands, and determining the final optimized design scheme of the coil.

[0047] During use, the islanded coils are regularly distributed outside the planar spiral coils and connected in series. Furthermore, the leads at both ends of the coils are made of the same material.

[0048] Considering the influence of eddy currents inside the square spiral coil and the external resistance of the coil on the coil quality, the method of reducing the internal cross-section of the coil and increasing the external cross-section of the coil is adopted to improve the coil quality.

[0049] Furthermore, the quality of the coil is further improved by adding small spiral islands around the coil.

[0050] The number of islands around the four sides of the square helical coil increases sequentially from 0. Finally, the magnetic field distribution and inductance value of various planar square helical coils are analyzed and compared through formulas, and the final optimized design scheme of the coil is determined to give it good magnetic sensing characteristics.

[0051] Similarly, the magnetic field distribution and inductance value of various planar square spiral coils can be analyzed and compared using COMSOL simulation software, and the final optimized design scheme of the coil can be determined to give it good magnetic sensing characteristics.

[0052] Example 2

[0053] Reference Figures 1-8 This is the second embodiment of the present invention, which differs from the first embodiment in that: after considering the self-inductance and mutual inductance of the spiral coil, the inductance value is calculated by the following formula:

[0054]

[0055] Where: L is the coil inductance; μ0 is the vacuum conductivity, with a value of 4π × 10⁻⁷ H·m⁻¹; l is the total length of the coil; n is the number of coil turns; w is the width of the coil wire; t is the thickness of the wire; d + The average distance between parallel segments on the same side of the square is the positive mutual inductance constituent factor.

[0056] Compared to Example 1, further, d +The average distance between parallel segments on the same side of the square, representing the positive mutual inductance constituent factors, can be calculated using the following closed formula:

[0057]

[0058] Where, d + is the average distance between parallel segments on the same side of the square, representing the positive mutual inductance factor; w is the width of the coil conductor; n is the number of coil turns; and s is the spacing between adjacent coil conductors.

[0059] Based on the above formula, the inductance L0 of the coil without islanding in series under ideal conditions can be calculated to be 10.213383 nH; the inductance LS of the islanded coil is 0.282769 nH. Therefore, the relationship between coil inductance and the number of islands can be derived as follows:

[0060] L = L0 + N·L S

[0061] Where: L is the coil inductance; L0 is the coil inductance value without series islanding; L S is the inductance value of the islanded coil; N is the number of islands.

[0062] The remaining structure is the same as that in Example 1.

[0063] Example 3

[0064] Reference Figures 1-13 This is the third embodiment of the present invention, which differs from the second embodiment in that the number of islands is derived by combining the above formula.

[0065] Compared to Example 2, further, under the same conditions, when the preset inductance value is 10.4nH, the number of islands needs to be increased from 0 to 1; when the preset inductance value is 10.6nH, the number of islands needs to be increased from 1 to 2; when the preset inductance value is 10.8nH, the number of islands needs to be increased from 2 to 3; when the preset inductance value is 11.0nH, the number of islands needs to be increased from 3 to 4; and when the preset inductance value is 12.1nH, the number of islands needs to be increased from 4 to 8.

[0066] This formula can be used in conjunction with COMSOL simulation software to analyze and compare the magnetic field distribution and inductance of various planar square spiral coils, and determine the final optimized design scheme of the coil. In COMSOL software, the model material is set to copper, the rest of the material is air, and a DC current of 1A is applied to the coil for excitation.

[0067] Considering the symmetry and aesthetics of the island coil distribution, as well as the influence of the scale factors of the spiral coil and the island coil, the final design scheme of the planar coil is a planar spiral coil with 8 small square spiral islands connected in series. The specific parameters of this structure are as follows: the number of coil turns is 8, the thickness is 5μm, the inner coil side length is 60μm, the outer coil side length is 400μm, and the spacing is 10μm; the number of island coil turns is 2, the thickness is 5μm, the inner coil side length is 60μm, the outer coil side length is 80μm, and the spacing is 10μm; the inner 4 coil turns have a line width of 10μm, and the outer 4 coil turns have a line width of 20μm.

[0068] Regarding the design scheme of the overall shape of the helical coil, triangular, pentagonal, and hexagonal helical coils with the same number of turns, wire width, and spacing were designed. Based on formulas or using COMSOL software for simulation, after applying a 1A DC excitation to each coil, the inductance value of the corresponding coil was calculated. The inductance values ​​were: triangular (11.288716171592217 nH), the irregularly shaped coil (12.186945570516718 nH), pentagonal (11.975219713506037 nH), and hexagonal (11.140928847375735 nH). Therefore, it can be deduced that the inductance value of the designed irregularly shaped coil is improved compared to the traditional helical coil.

[0069] The overall technical solution involves introducing a variable cross-section structure design to reduce the eddy current loss of the internal coil and increase the cross-section of the external coil to reduce the internal resistance loss, thereby improving the performance of the planar coil. Small spiral islanded coils are added around the main coil, and these islanded coils are connected in series to further improve the coil quality. Based on the formula (which can also be used through COMSOL simulation software), the influence of the number of islands on the coil performance is explored by continuously increasing the number of islands around the four sides of the square spiral coil.

[0070] Adding small spiral islanded coils in series around the coil results in a denser induced magnetic field distribution when the islanded coil is excited by current. The inductance of a commonly used spiral coil is increased when islanded coils are connected in series. The more islanded coils added in series around the coil, the greater the inductance of the coil.

[0071] The remaining structure is the same as that in Example 2.

[0072] It is important to note that the constructions and arrangements of this application shown in several different exemplary embodiments are merely illustrative. Although only a few embodiments are described in detail in this disclosure, those who consult this disclosure will readily understand that many modifications are possible (e.g., changes in the size, dimensions, structure, shape, and proportions of various elements, as well as parameter values ​​(e.g., temperature, pressure, etc.), mounting arrangements, use of materials, color, orientation, etc.) without substantially departing from the novel teachings and advantages of the subject matter described in this application). For example, an element shown as integrally formed may be composed of multiple parts or elements, the position of elements may be inverted or otherwise altered, and the nature or number or position of discrete elements may be changed or altered. Therefore, all such modifications are intended to be included within the scope of the invention. The order or sequence of any process or method steps may be changed or rearranged according to alternative embodiments. In the claims, any "device plus function" clause is intended to cover the structure described herein that performs the function, and not only structurally equivalent but also equivalent in structure. Other substitutions, modifications, alterations, and omissions may be made in the design, operation, and arrangement of the exemplary embodiments without departing from the scope of the invention. Therefore, the present invention is not limited to the specific embodiments, but extends to various modifications that still fall within the scope of the appended claims.

[0073] Furthermore, in order to provide a concise description of exemplary embodiments, not all features of actual embodiments (i.e., those features that are not relevant to the currently considered best mode for carrying out the invention, or those features that are not relevant to implementing the invention) may be omitted.

[0074] 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, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A method for optimizing the magnetic sensing characteristics of an islanded series-connected variable cross-section micro / nano coil, characterized in that: include, The design is based on a planar square spiral coil. Based on the influence of eddy currents inside the square spiral coil and external resistance on coil quality, the method of reducing the cross-section of the internal coil and increasing the cross-section of the external coil is adopted to improve coil quality. Add small spiral islands around the coil; The magnetic field distribution and inductance of planar square spiral coils with different numbers of islands were analyzed and compared, and the final optimized design scheme of the coil was determined. The analysis and comparison were conducted by setting the material to copper and the rest to air; and applying a 1A DC current excitation to the coil. Taking into account the self-inductance and mutual inductance of the spiral coil, the inductance value is calculated using the following formula: Where: L is the coil inductance; Let V be the vacuum conductivity, and its value is... l is the total length of the coil; n is the number of turns in the coil; w is the width of the coil wire; t is the thickness of the wire; d + The average distance between parallel segments on the same side of the square is the positive mutual inductance constituent factor. The average distance between parallel segments on the same side of the square, where the positive mutual inductance constituent factors are located, can be calculated using the following closed formula: Where s is the spacing between adjacent wires of the coil; The formula for determining the relationship between the coil inductance L and the number of islands is as follows: Where: L is the coil inductance; This is the inductance value of the coil without series connection to the island; is the inductance value of the islanded coil; N is the number of islands; The islanded coil has a thickness of 5μm, an inner coil side length of 60μm, an outer coil side length of 80μm, and a spacing of 10μm.

2. The method for optimizing the magnetic sensing characteristics of islanded series-connected variable cross-section micro / nano coils according to claim 1, characterized in that: The islanded coils are regularly distributed outside the planar spiral coils and connected in series.

3. The method for optimizing the magnetic sensing characteristics of an islanded series-connected variable cross-section micro / nano coil according to claim 1 or 2, characterized in that: The leads at both ends of the islanded coil are connected by wires of the same material.

4. The method for optimizing the magnetic sensing characteristics of islanded series-connected variable cross-section micro / nano coils according to claim 3, characterized in that: Under the same conditions, When the preset inductance value is 10.4nH, the number of islands needs to be increased from 0 to 1; When the preset inductance value is 10.6nH, the number of islands needs to be increased from 1 to 2; When the preset inductance value is 10.8nH, the number of islands needs to be increased from 2 to 3; When the preset inductance value is 11.0nH, the number of islands needs to be increased from 3 to 4; When the preset inductance value is 12.1nH, the number of islands needs to be increased from 4 to 8.

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