An outer magnetic ring type deflection coil parameterized modeling and magnetic field distribution simulation method

Abstract

The application discloses a method for parameterized modeling and magnetic field distribution simulation of an outer magnetic ring type deflection coil, which comprises the following steps: establishing a three-dimensional simulation model of the outer magnetic ring type deflection coil; the three-dimensional simulation model of the outer magnetic ring type deflection coil comprises a winding model and an outer magnetic ring model; material definition, mesh division and boundary condition assignment are performed on the established three-dimensional simulation model of the outer magnetic ring type deflection coil; simulation analysis is performed on the three-dimensional simulation model of the outer magnetic ring type deflection coil after the assignment, and spatial magnetic induction intensity distribution of the deflection coil is obtained. The method for parameterized modeling is adopted to perform three-dimensional modeling on the outer magnetic ring type deflection coil, effectively solves the problems of difficulty and complexity in three-dimensional modeling of the outer magnetic ring type deflection coil, and effectively simulates under the premise of not losing structural authenticity. The application can provide theoretical guidance for design and manufacturing of the outer magnetic ring type deflection coil, thereby saving design cost, shortening design period, and improving design and production efficiency.

Description

Technical Field

[0001] This invention relates to the fields of 3D modeling and simulation analysis, and in particular to a method for parametric modeling and magnetic field distribution simulation of an external magnetic ring deflection coil. Background Technology

[0002] In the field of additive manufacturing, selective electron beam melting (SEBLM) is a popular powder bed metal additive manufacturing process. This process uses a computer-controlled electron beam to selectively melt metal powder on a powder bed according to the cross-sectional information of the part. After scanning and forming one layer, the stage lowers to a certain height, and the entire part is formed by stacking layers. The electron beam scans and melts within a certain range to obtain the cross-sectional pattern. Deflection coils are needed to control the printing position of the electron beam on the powder bed. To ensure stable deflection of the electron beam, the deflection coils must generate a uniform magnetic field of equal magnitude.

[0003] Currently, commonly used deflection coils include pole shoe deflection coils, Helmholtz deflection coils, and external magnetic ring deflection coils. Among them, external magnetic ring deflection coils can generate a stable and reliable uniform magnetic field. However, due to the complexity of the coil design and winding, the design and manufacturing cycle is long. When changing parameters such as the coil geometry and number of turns, the program is cumbersome. Currently, the commonly used simulation methods for external magnetic ring deflection coils are mostly two-dimensional model simulations. On the one hand, they can only obtain the distribution of magnetic induction intensity on the plane and cannot analyze the distribution of magnetic induction intensity in the space of the deflection coil. On the other hand, they ignore the contribution and influence of the winding on the magnetic induction intensity in space, making it impossible to perform a more accurate simulation of this type of deflection coil. Summary of the Invention

[0004] To address the problems of inaccurate simulations and unintuitive magnetic field analysis after deflection coil design caused by difficulties in modeling existing external magnetic ring deflection coils or their deviation from actual shapes, this invention aims to propose a parametric modeling and magnetic field distribution simulation method for external magnetic ring deflection coils. Through parametric modeling, the magnetic field is simulated and analyzed using relevant finite element analysis software, which can quickly determine the spatial magnetic field distribution around the deflection coil under different parameters. This provides theoretical guidance for the design and manufacturing of this type of deflection coil, improving design and production efficiency.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0006] A parametric modeling and magnetic field distribution simulation method for an external magnetic ring type deflection coil includes the following steps:

[0007] Step (1): Establish a three-dimensional simulation model of the external magnetic ring deflection coil; the three-dimensional simulation model of the external magnetic ring deflection coil includes a winding model and an external magnetic ring model;

[0008] Step (2) involves defining the material, meshing, and assigning boundary conditions to the three-dimensional simulation model of the external magnetic ring deflection coil established in step (1).

[0009] Step (3) Perform simulation analysis on the three-dimensional simulation model of the external magnetic ring deflection coil after the values ​​are assigned in step (2) to obtain the spatial magnetic induction intensity distribution of the deflection coil.

[0010] Furthermore, the establishment of the winding model includes the following steps:

[0011] Establish feature circles 1 to M and feature curves; use feature circles 1 to M as sweep profiles and the feature curves corresponding to each feature circle as sweep paths to build a winding model using simulation software.

[0012] Furthermore, the coordinates of the centers of characteristic circles 1 to M in the xy plane are:

[0013]

[0014] In the formula, D0 is the diameter of the deflection coil, and d x Let θ be the diameter of each segment of the winding. x It is the azimuth angle;

[0015] The diameter of each characteristic circle 1 to characteristic circle M is d. x .

[0016] Furthermore, the azimuth angle θ x Calculated using the following formula:

[0017]

[0018] M is the number of segments in deflection coil winding 1, and x = 1 to M.

[0019] Furthermore, the diameter d of each segment of the winding x Calculated using the following formula:

[0020]

[0021] Where, d wire Where N is the diameter of the conductor, and the number of turns in each segment is N. x as follows:

[0022]

[0023] In the formula, N t This represents the total number of turns in the winding.

[0024] Furthermore, the characteristic curve is established through the following process:

[0025] The coordinates of the two endpoints of the characteristic line segment x1 corresponding to the characteristic curve x in the spatial Cartesian coordinate system are respectively and The coordinates of the two endpoints of the characteristic line segment x2 corresponding to the characteristic curve x in the spatial Cartesian coordinate system are as follows: and

[0026] The parametric equation of the characteristic arc x' corresponding to the characteristic curve x is:

[0027]

[0028] In the formula, α is a parameter, and b x h is the primary height control factor. x It is the second-highest control factor.

[0029] Furthermore, the outer magnetic ring model has an inner diameter of D. w =D0+4d1, a hollow cylinder with thickness t and length L, the central axis of the cylinder coincides with the xy plane.

[0030] Furthermore, the boundary conditions include the number of turns in each winding, and the magnitude and direction of the current in the entire deflection coil.

[0031] Furthermore, determine whether the spatial magnetic induction intensity distribution meets the design requirements. If not, change the corresponding parameters of the deflection coil, repeat step (1), and perform simulation analysis again.

[0032] Compared with the prior art, the present invention has the following beneficial effects:

[0033] This invention innovatively constructs a three-dimensional simulation model of an external magnetic ring deflector coil. Compared with a two-dimensional simulation model, it considers the contribution and influence of the winding on the overall magnetic induction intensity distribution in the spatial dimension, thus improving the simulation effect. This invention employs a parametric method for three-dimensional modeling of the external magnetic ring deflector coil, effectively solving the problems of difficulty and complexity in three-dimensional modeling of external magnetic ring deflector coils, and enabling effective simulation without sacrificing structural realism. For external magnetic ring deflector coils with different dimensional or electrical parameters, only the corresponding design parameters need to be modified to adjust or fine-tune the coil's dimensions and ampere-turns, facilitating subsequent parametric simulation work. This invention can provide theoretical guidance for the design and manufacturing of external magnetic ring deflector coils, thereby saving design costs, shortening the design cycle, and improving design and production efficiency. Attached Figure Description

[0034] To more clearly and intuitively illustrate the solutions of the embodiments of the present invention, the accompanying drawings required for the embodiments will be briefly introduced below. 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.

[0035] Figure 1 This is a flowchart of a three-dimensional modeling and spatial magnetic field distribution simulation method for an external magnetic ring type deflection coil according to the present invention;

[0036] Figure 2 This is a schematic diagram showing the dimensions of the feature circle and the center circle according to an embodiment of the present invention;

[0037] Figure 3 It is a contour curve diagram according to an embodiment of the present invention;

[0038] Figure 4 This is a schematic diagram of each segment of the winding according to an embodiment of the present invention;

[0039] Figure 5 This is a schematic diagram showing the positions of two windings according to an embodiment of the present invention;

[0040] Figure 6 This is a schematic diagram of the feature structure according to an embodiment of the present invention;

[0041] Figure 7 This is a parameterized three-dimensional model diagram of the deflection coil according to an embodiment of the present invention;

[0042] Figure 8 This is a schematic diagram of the current direction of feature structure 1 according to an embodiment of the present invention. Detailed Implementation

[0043] The embodiments of the present invention will now be described with reference to the accompanying drawings. These embodiments are merely exemplary and intended to explain the invention, and should not be construed as limiting it. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0044] A method for parametric modeling and magnetic field distribution simulation of an external magnetic ring deflection coil according to an embodiment of the present invention mainly includes the following steps:

[0045] Step (1): Establish a 3D simulation model of the external magnetic ring deflection coil using the pre-processing functions of simulation software such as Comsol, Ansys, and Maxwell, or other 3D modeling software such as SolidWorks, Catia, and UG. The parametric model establishment process of the deflection coil is as follows:

[0046] The external magnetic ring type deflection coil consists of two windings, namely deflection coil winding 1 and deflection coil winding 2. The two windings are wound with the same wire and symmetrically wrapped around the deflection coil frame. A cylindrical magnetic ring is fitted around the outside of the windings. Due to the symmetrical structure, only one winding model needs to be built when modeling, and the other winding model can be obtained by "mirroring".

[0047] 1. The deflection coil winding is divided into M segments evenly distributed on the circumference, named segment 1, segment 2, ..., segment M. The diameter of the circumference is the diameter D0 of the deflection coil. The angle between each segment is... The azimuth angle θ between the center of each segment of the circle and the x-axis x Satisfying (x=1~M)

[0048]

[0049] Based on the characteristics of the turns distribution of the internal magnetic ring type deflection coil, the total number of turns of the winding is N. t Then the number of turns N in each segment x satisfy:

[0050]

[0051] Since the actual number of turns is an integer during winding, the result of the above formula is rounded to the nearest integer. The diameter d of each segment of the winding... x satisfy

[0052]

[0053] According to the azimuth angle θ x The diameter D0 of the deflection coil and the diameters d of each segment x The coordinates of the centers of each characteristic circle 1 to characteristic circle M in the xy plane are:

[0054]

[0055] The diameters of each characteristic circle 1 to characteristic circle M are also d. x .

[0056] 2. Establish characteristic curves;

[0057] Each characteristic curve (characteristic curve x) consists of two characteristic line segments (characteristic line segment x1 and characteristic line segment x2) and one characteristic circular arc (characteristic circular arc x'). The lower endpoint of characteristic line segment x1 coincides with the center of the characteristic circle. Both characteristic line segments x1 and x2 are perpendicular to the xy plane and have a length equal to half the coil length L. Characteristic line segments x1 and x2 are symmetrical about the yz plane. The two ends of characteristic circular arc x' coincide with the upper endpoints of characteristic line segments x1 and x2, respectively. Therefore, the coordinates of the two endpoints of characteristic line segments x1 and x2 corresponding to characteristic curve x in the spatial Cartesian coordinate system are as follows:

[0058]

[0059] The parametric equation of the characteristic arc x' corresponding to the characteristic curve x is:

[0060]

[0061] The range of parameter α is [θ x ,π-θ x ];b x h is the primary height control factor. x The second height control factor is a parameter that controls the height of the vertex position of the corresponding feature arc x', thus preventing simulation errors caused by the intersection of the windings.

[0062] This allows the characteristic curve to be established.

[0063] Using feature circles 1 to M as sweep profiles and the feature curves corresponding to each feature circle as sweep paths, the winding model is established using the preprocessing tools of simulation software or the "sweep" function in modeling software.

[0064] 3. Establish an outer magnetic ring model, which is an outer magnetic ring with an inner diameter of D. w =D0+4d1, a hollow cylinder with thickness t and length L, the central axis of the cylinder coincides with the xy plane.

[0065] Based on the determined number of winding segments M, coil diameter D0, and total number of turns N of the deflection coil. t Coil length L, wire diameter d wire Height control factor b x h x By determining the thickness t of the outer magnetic ring, a unique winding model can be established. If the model of the deflection coil needs to be changed later, only the above parameters need to be changed. This is the highlight of the parametric simulation modeling method.

[0066] In this embodiment, the winding has 6 segments, i.e., M=6, the diameter D0 is 80mm, and the total number of turns N is... t The coil length is 63, the wire diameter is 80mm, and the coil length is d. wire =1mm, outer magnetic ring thickness 20mm, height control factor values ​​are shown in the table below, unit: mm.

[0067]

[0068]

[0069] In the table, b1 is the first altitude control factor 1, b2 is the second altitude control factor 2, b3 is the third altitude control factor 3, b4 is the fourth altitude control factor 4, b5 is the fifth altitude control factor 5, and b6 is the fifth altitude control factor 6; h1 is the second altitude control factor 1, h2 is the second altitude control factor 2, h3 is the second altitude control factor 3, h4 is the second altitude control factor 4, h5 is the second altitude control factor 5, and h6 is the second altitude control factor.

[0070] Based on the specific values ​​of each parameter, the specific parameters of each section of the winding can be obtained from formulas 1, 2, 3, and 4, as shown in the table below.

[0071] Section 1 Section 2 Section 3 Section 4 Section 5 Section 6 Azimuth θ 7.5° 22.5° 37.5° 52.5° 67.5° 82.5° Number of turns N 16 15 13 10 6 2 diameter d 4mm 3.87mm 3.61mm 3.16mm 2.45mm 1.41mm

[0072] Based on the diameter and center coordinates above, feature circles 1 to 6 can be constructed on the xy plane. They are all tangent to the central circle with the origin of the Cartesian coordinate system as its center and a diameter of D0. The central circle and feature circles 1 to 6 are as follows: Figure 2 As shown. Based on the parameter information of each feature line segment and feature arc in the feature curve, the feature curve is established as follows. Figure 3 As shown, using feature circles 1 to 6 as sweep contours and feature curves 1 to 6 as sweep paths, segments 1 to 6 of winding 1 are established using the sweep function in modeling or simulation software, as follows. Figure 4 As shown. Segments 1 to 6 are mirrored in the xy plane to obtain winding 1. Winding 1 is then mirrored in the xz plane to obtain winding 2. The characteristic structure 1 of the coil is as follows. Figure 5 As shown. Feature structure 2 is constructed in exactly the same way as feature structure 1, except for the size of the central circle. The diameter of the central circle of feature structure 1 is the coil diameter D0, while the diameter of the central circle of feature structure 2 is D0+2d1. Furthermore, feature structures 1 and 2 are at 90° to each other on the z-axis. The models of feature structures 1 and 2 are as follows. Figure 6 As shown. The three-dimensional model of the entire outer magnetic ring deflector coil is as follows. Figure 7 As shown.

[0073] Step (2) defines the material for the three-dimensional simulation model of the deflection coil established in step (1). Feature structures 1 and 2 of the deflection coil are wound with copper wire, therefore the material is set to copper. This can be directly imported from the simulation software's material library, or its relative permeability can be set to 1, relative permittivity to 1, and conductivity to 5.998 × 10⁻⁶. 7 S / m. The outer magnetic ring of the deflection coil is made of ferrite material, which can be directly imported from the material library of the simulation software.

[0074] Step (3) involves meshing the three-dimensional simulation model of the deflection coil established in step (1). The mesh of the parametric three-dimensional model of the deflection coil is defined as a free tetrahedral mesh, with a maximum element size of 1 mm. The smaller the maximum element size, the finer the mesh.

[0075] Step (4) assigns boundary conditions to the three-dimensional simulation model of the deflection coil established in step (1), mainly including the number of turns of each winding, the magnitude and direction of the current in the entire deflection coil: the number of turns of each segment of the winding in the three-dimensional simulation model of the deflection coil is determined according to the number of turns N. xGiven that the actual deflection coil is wound with a single wire, the current in each turn of the wire in all windings is equal and set to I. coil The current direction is determined by the actual design values ​​and is given on characteristic circles 1 to M according to the actual situation. The current direction on characteristic circles 1 to M is unified, and each winding forms its own loop. In this embodiment, the X-direction current I... coilX The current I in the Y direction is 1.5A. coilY The current is 2A. The current direction of feature structure 1 is from bottom to top in the cross-section of feature circles 1 to 6. The current direction of feature structure 2 is the same as that of feature structure 1. Figure 8 As shown.

[0076] Step (5) uses finite element analysis software to perform simulation analysis on the parameterized three-dimensional model after the values ​​assigned in step (4). The post-processing tool of the simulation software is used to obtain the spatial magnetic induction intensity distribution of the deflection coil.

[0077] Step (6) determines whether the spatial magnetic induction intensity distribution obtained in step (5) meets the design requirements. If it does, the simulation analysis process is completed. If it does not, the corresponding parameters of the deflection coil, such as the total number of turns of the winding, are changed, and step (1) is performed again to conduct the simulation analysis.

[0078] The finite element method used in this invention employs Comsol Multiphysics software to model and simulate the parametric model and spatial magnetic field distribution of the external magnetic ring deflector coil. By selecting a suitable dataset, the magnitude and distribution of the magnetic field in the space, surface, line, and point around the deflector coil can be obtained quickly and accurately, making it suitable for the design and analysis of external magnetic ring deflector coils.

[0079] For ease of explanation, the use of relational terms such as "1" and "2" in the embodiments is merely to distinguish one object from another that has the same name, and does not necessarily require or imply any such actual relationship or order between these objects.

[0080] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for parametric modeling and magnetic field distribution simulation of an external magnetic ring deflector coil, characterized in that, Includes the following steps: Step (1): Establish a three-dimensional simulation model of the external magnetic ring deflection coil; the three-dimensional simulation model of the external magnetic ring deflection coil includes the winding model and the external magnetic ring model; Step (2) defines the material, meshes, and assigns boundary conditions to the three-dimensional simulation model of the external magnetic ring deflection coil established in step (1). Step (3) Perform simulation analysis on the three-dimensional simulation model of the external magnetic ring deflection coil after the values ​​are assigned in step (2) to obtain the spatial magnetic induction intensity distribution of the deflection coil. The establishment of the winding model includes the following steps: Establish feature circle 1 ~ feature circle M and characteristic curves; respectively using characteristic circle 1 to characteristic circle... M To sweep the contour, the characteristic curve corresponding to each feature circle is used as the sweep path, and a winding model is built using simulation software. Feature circle 1 ~ Feature circle M The coordinates of the center of the circle in the xy plane are: In the formula, D 0 represents the diameter of the deflection coil. d x The diameter of each section of the winding, θ x It is the azimuth angle; Feature circles 1 to feature circles M The diameter is d x ; Azimuth θ x Calculated using the following formula: M This refers to the number of segments in deflection coil winding 1. x =1~ M ; diameter of each section of the winding d x Calculated using the following formula: in, d wire The conductor diameter and the number of turns in each segment are given. N x as follows: In the formula, N t This represents the total number of turns in the winding. The characteristic curve is established through the following process: characteristic curve x Corresponding feature line segments x The coordinates of the two endpoints of 1 in the spatial Cartesian rectangular coordinate system are respectively characteristic curve x Corresponding feature line segments x The coordinates of the two endpoints of 2 in the Cartesian coordinate system are as follows: characteristic curve x Corresponding feature arc x The parametric equation for ' is: In the formula, α is a parameter. b x As the primary height control factor, h x It is the second-highest control factor.

2. The method for parametric modeling and magnetic field distribution simulation of an external magnetic ring deflector coil according to claim 1, characterized in that, The outer magnetic ring model has an inner diameter of D w =D 0+ 4d 1. Thickness is t , length is L A hollow cylinder, with its central axial surface coinciding with the xy plane.

3. The method for parametric modeling and magnetic field distribution simulation of an external magnetic ring deflector coil according to claim 1, characterized in that, Boundary conditions include the number of turns in each winding, the magnitude and direction of the current in the entire deflection coil.

4. The method for parametric modeling and magnetic field distribution simulation of an external magnetic ring deflector coil according to claim 1, characterized in that, Determine whether the spatial magnetic induction intensity distribution meets the design requirements. If not, change the corresponding parameters of the deflection coil and repeat step (1) to perform simulation analysis again.

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