Method and device for optimizing uniformity of central magnetic field of annular segmented iron yoke

Abstract

The invention provides an annular segmented iron yoke center magnetic field uniformity optimization method and device, relates to the technical field of superconducting electrical iron yokes, and solves the technical problem that the uniformity of a superconducting magnet center magnetic field is difficult to improve in the prior art. The method specifically comprises the following steps: acquiring physical basic parameters of the superconducting magnet; establishing a two-dimensional axisymmetric calculation model, determining radial and axial calculation ranges, and generating a two-dimensional grid coordinate matrix; calculating an initial static magnetic field by using the two-dimensional grid coordinate matrix based on the Biot-Savart law and the axial symmetry characteristic; constructing an annular yoke multi-parameter optimization problem, and performing global parameter search by adopting a genetic algorithm to obtain yoke optimization parameters; based on the magnetic dipole theory and the saturation characteristic of the ferromagnetic material, a correction model of the yoke to the magnetic field is established by combining yoke optimization parameters, an additional magnetic field generated by the yoke is calculated, the additional magnetic field and the initial static magnetic field are superposed, and the total magnetic field intensity is obtained. The method is used for optimizing the uniformity of the iron yoke center magnetic field.

Description

Technical Field

[0001] This application relates to the field of superconducting electric iron yoke technology, and in particular to a method and apparatus for optimizing the uniformity of the central magnetic field of a ring-shaped segmented iron yoke. Background Technology

[0002] Improving the magnetic field uniformity in the central region of a superconducting magnet is crucial for its reliable application in precision measurement, medical imaging, and other fields. Existing technologies often employ symmetrically distributed fixed boss structures to improve magnetic field uniformity. Specifically, this involves pre-designing bosses with fixed positions and sizes, arranging the bosses based on the principle of symmetry, verifying the magnetic field distribution using finite element analysis, and manually adjusting the boss parameters to achieve the target magnetic field uniformity. However, these methods rely on manual experience or local parameter scanning, have long design cycles, are difficult to find globally optimal solutions, and do not fully consider ferromagnetic material saturation, magnetic coupling effects between bosses, and the stability of the central magnetic field. Parameters such as boss position, size, and gap are adjusted independently, lacking a systematic collaborative optimization model. Therefore, existing technologies face the technical challenge of failing to improve the uniformity of the central magnetic field of superconducting magnets. Summary of the Invention

[0003] This application provides a method and apparatus for optimizing the uniformity of the central magnetic field of a segmented annular iron yoke, which solves the technical problem that it is difficult to improve the uniformity of the central magnetic field of a superconducting magnet in the prior art.

[0004] To achieve the above objectives, this application adopts the following technical solution: Firstly, a method for optimizing the uniformity of the central magnetic field of a segmented toroidal yoke is provided, comprising: obtaining the fundamental physical parameters of a superconducting magnet; the fundamental physical parameters include geometric parameters, electromagnetic parameters, material parameters, and yoke constraints; establishing a two-dimensional axisymmetric calculation model based on the fundamental physical parameters, determining the radial and axial calculation ranges of the covering coil, yoke, and magnetic field attenuation region, and generating a two-dimensional grid coordinate matrix; calculating the initial static magnetic field generated by the superconducting coil in space using the two-dimensional grid coordinate matrix based on the Biot-Savart law and axisymmetric characteristics; constructing a multi-parameter optimization problem for the toroidal yoke, using a genetic algorithm for global parameter search to obtain the optimized parameters of the yoke; establishing a correction model of the yoke on the magnetic field based on magnetic dipole theory and the saturation characteristics of ferromagnetic materials, combined with the optimized parameters of the yoke, calculating the additional magnetic field generated by the yoke, and superimposing the additional magnetic field with the initial static magnetic field to obtain the total magnetic field strength.

[0005] Based on the above technical solution, the method for optimizing the uniformity of the central magnetic field of the annular segmented iron yoke provided in this application can efficiently achieve the global optimal improvement of the uniformity of the central magnetic field by combining multi-parameter collaborative optimization and global search of genetic algorithm with ferromagnetic material saturation characteristic modeling and central field stability control, while ensuring magnetic field stability.

[0006] In conjunction with the first aspect mentioned above, in one possible implementation, the geometric parameters include the inner diameter, outer diameter, and height of the coil; the electromagnetic parameters include the current density and vacuum permeability; the material parameters include the saturation magnetic induction intensity, relative permeability, and material density of electrical pure iron; and the yoke constraints include the number of yokes on one side, the maximum width of the yoke, the maximum depth of the yoke, and the range of the gap between the yoke and the coil.

[0007] In conjunction with the first aspect mentioned above, in one possible implementation, after establishing a correction model of the magnetic field by the iron yoke based on the magnetic dipole theory and the saturation characteristics of ferromagnetic materials, and combining the optimized parameters of the iron yoke, calculating the additional magnetic field generated by the iron yoke, and superimposing the additional magnetic field with the initial static magnetic field to obtain the total magnetic field distribution, the method further includes: calculating the uniformity improvement rate based on the non-uniformity of the initial static magnetic field and the non-uniformity of the total magnetic field; and verifying whether the position distribution, spacing, and gap between the iron yoke and the coil meet the preset constraint requirements.

[0008] In conjunction with the first aspect mentioned above, in one possible implementation, a two-dimensional axisymmetric calculation model is established based on physical fundamental parameters to determine the radial and axial calculation ranges of the covering coil, yoke, and magnetic field attenuation region, and to generate a two-dimensional mesh coordinate matrix. This includes: determining the radial and axial calculation boundaries of the covering coil, yoke, and magnetic field attenuation region based on geometric parameters and yoke constraints; setting the number of radial and axial mesh points and calculating the mesh spacing; generating the coordinates of each mesh point based on the mesh spacing and constructing a two-dimensional mesh coordinate matrix.

[0009] In conjunction with the first aspect mentioned above, in one possible implementation, based on the Biot-Savart law and axisymmetric characteristics, the initial static magnetic field generated by the superconducting coil in space is calculated using a two-dimensional grid coordinate matrix. This includes: calculating the axial magnetic field distribution using an analytical method based on the contributions of the coil's inner and outer diameters; approximating the outer magnetic field using an exponential decay model; characterizing the axial decay and radial growth saturation characteristics of the magnetic field using an axial decay function and a radial growth function; introducing an end effect correction factor to correct the magnetic field deviation at the coil ends; and calculating the average magnetic field in the central region based on the two-dimensional grid coordinate matrix to obtain the initial static magnetic field.

[0010] In conjunction with the first aspect mentioned above, one possible implementation involves constructing a multi-parameter optimization problem for a circular iron yoke, and using a genetic algorithm to perform a global parameter search to obtain the iron yoke optimization parameters. These parameters include: setting the position, width, depth, and gap of each iron yoke as optimization variables; constructing an objective function containing magnetic field inhomogeneity, maximum relative deviation, central field change rate, and constraint violation penalty terms; setting iron yoke order constraints, spacing constraints, and boundary constraints; configuring the population size, maximum number of generations, crossover probability, mutation probability, and convergence tolerance of the genetic algorithm; and performing a global search using the genetic algorithm to output the iron yoke optimization parameters.

[0011] In conjunction with the first aspect mentioned above, in one possible implementation, based on magnetic dipole theory and the saturation characteristics of ferromagnetic materials, a correction model for the magnetic field of the iron yoke is established by combining the optimized parameters of the iron yoke. The additional magnetic field generated by the iron yoke is calculated, and the additional magnetic field is superimposed with the initial static magnetic field to obtain the total magnetic field strength. This includes: calculating the effective magnetization and volume of the iron yoke based on the optimized parameters of the iron yoke; calculating the magnetic moment of the iron yoke based on the effective magnetization and volume, and obtaining the additional magnetic field by combining the magnetic dipole theory; introducing a geometric attenuation factor, and superimposing the additional magnetic fields of each iron yoke with the initial static magnetic field to obtain the total magnetic field strength.

[0012] In conjunction with the first aspect mentioned above, in one possible implementation, the magnetic moment of the yoke is calculated based on the effective magnetization and volume, and the additional magnetic field is obtained by combining the magnetic dipole theory. This includes: calculating the spatial distance between the coordinates of the observation point and the coordinates of the yoke center; calculating the direction cosine based on the axial difference, radial difference, and spatial distance between the observation point and the yoke center; and calculating the additional magnetic field at the observation point based on the magnetic moment, spatial distance, and direction cosine.

[0013] In conjunction with the first aspect mentioned above, in one possible implementation, based on the magnetic moment, spatial distance, and direction cosine, the additional magnetic field at the observation point is calculated to satisfy the following formula:

[0014] in, To add a magnetic field, where is the free permeability and m is the magnetic moment. Here, denoted by 'direction cosine', and 'dist' represents the spatial distance.

[0015] Secondly, a device for optimizing the uniformity of the central magnetic field of a segmented annular iron yoke is provided, comprising: a communication unit and a processing unit; the communication unit is used to acquire the basic physical parameters of the superconducting magnet; the basic physical parameters include geometric parameters, electromagnetic parameters, material parameters, and iron yoke constraints; the processing unit is used to establish a two-dimensional axisymmetric calculation model based on the basic physical parameters, determine the radial and axial calculation ranges of the covering coil, iron yoke, and magnetic field attenuation region, and generate a two-dimensional grid coordinate matrix; based on the Biot-Savart law and axisymmetric characteristics, the initial static magnetic field generated by the superconducting coil in space is calculated using the two-dimensional grid coordinate matrix; a multi-parameter optimization problem of the annular iron yoke is constructed, and a genetic algorithm is used for global parameter search to obtain the optimized parameters of the iron yoke; based on the magnetic dipole theory and the saturation characteristics of ferromagnetic materials, a correction model of the iron yoke on the magnetic field is established in combination with the optimized parameters of the iron yoke, the additional magnetic field generated by the iron yoke is calculated, and the additional magnetic field is superimposed with the initial static magnetic field to obtain the total magnetic field strength.

[0016] This application provides a method and apparatus for optimizing the uniformity of the central magnetic field of a segmented annular iron yoke. It can overcome the limitations of traditional manual experience-based adjustments, significantly improve the uniformity of the central magnetic field of a superconducting magnet and design efficiency, shorten the design cycle, and solve the technical problem that it is difficult to improve the uniformity of the central magnetic field of a superconducting magnet in the existing technology.

[0017] It should be understood that the descriptions of technical features, technical solutions, beneficial effects, or similar language in this application do not imply that all features and advantages can be achieved in any single embodiment. Rather, it is understood that the description of a feature or beneficial effect means that a specific technical feature, technical solution, or beneficial effect is included in at least one embodiment. Therefore, the descriptions of technical features, technical solutions, or beneficial effects in this specification do not necessarily refer to the same embodiment. Furthermore, the technical features, technical solutions, and beneficial effects described in this embodiment can be combined in any suitable manner. Those skilled in the art will understand that embodiments can be implemented without one or more specific technical features, technical solutions, or beneficial effects of a particular embodiment. In other embodiments, additional technical features and beneficial effects may be identified in specific embodiments that do not embody all embodiments. Attached Figure Description

[0018] Figure 1 A flowchart illustrating a method for optimizing the uniformity of the central magnetic field of a segmented annular iron yoke, provided in an embodiment of this application; Figure 2 A flowchart illustrating another method for optimizing the uniformity of the central magnetic field of a segmented annular iron yoke, provided in an embodiment of this application; Figure 3 A flowchart illustrating another method for optimizing the uniformity of the central magnetic field of a segmented annular iron yoke, provided in an embodiment of this application; Figure 4 A flowchart illustrating another method for optimizing the uniformity of the central magnetic field of a segmented annular iron yoke, provided in an embodiment of this application; Figure 5 A flowchart illustrating another method for optimizing the uniformity of the central magnetic field of a segmented annular iron yoke, provided in an embodiment of this application; Figure 6 A flowchart illustrating another method for optimizing the uniformity of the central magnetic field of a segmented annular iron yoke, provided in an embodiment of this application; Figure 7 This application provides a schematic diagram of the magnetic field distribution of a superconducting magnet before optimization. Figure 8 This application provides a schematic diagram of the uniformity distribution of the central region before optimization. Figure 9 A schematic diagram of an optimized annular segmented yoke layout provided in an embodiment of this application; Figure 10 This application provides an optimized magnetic field distribution schematic diagram. Figure 11 This is a schematic diagram of an optimized uniformity distribution provided in an embodiment of this application; Figure 12 This is a schematic diagram of a device for optimizing the uniformity of the central magnetic field of a segmented annular iron yoke, as provided in an embodiment of this application. Detailed Implementation

[0019] In the description of this application, unless otherwise stated, " / " means "or," for example, A / B can mean A or B. The "and / or" in this document is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A alone, A and B simultaneously, and B alone. Furthermore, "at least one" means one or more, and "multiple" means two or more. The terms "first," "second," etc., do not limit the quantity or order of execution, and "first," "second," etc., do not necessarily imply differences.

[0020] It should be noted that, in this application, the terms "exemplary" or "for example" are used to indicate that something is being described as an example, illustration, or illustration. Any embodiment or design described as "exemplary" or "for example" in this application should not be construed as being more preferred or advantageous than other embodiments or design solutions. Specifically, the use of terms such as "exemplary" or "for example" is intended to present the relevant concepts in a concrete manner.

[0021] To address the technical problem of difficulty in improving the uniformity of the central magnetic field of superconducting magnets in existing technologies, this application provides a method for optimizing the uniformity of the central magnetic field of a toroidal segmented iron yoke. This method includes: acquiring the geometric, electromagnetic, and material parameters of the superconducting magnet; establishing a two-dimensional axisymmetric calculation model and generating a two-dimensional grid coordinate matrix; calculating the initial static magnetic field based on the Biot-Savart law and axisymmetric characteristics; constructing a multi-parameter optimization problem for the toroidal iron yoke and obtaining the optimized parameters using a genetic algorithm; establishing a correction model combining magnetic dipole theory and the saturation characteristics of ferromagnetic materials; and superimposing the additional magnetic field of the iron yoke and the initial static magnetic field to obtain the total magnetic field. Based on this, the global optimal improvement of the uniformity of the central magnetic field of the superconducting magnet can be achieved, while ensuring the stability of the central magnetic field, significantly improving design efficiency and shortening the design cycle.

[0022] like Figure 1 As shown in the embodiments of this application, the method for optimizing the uniformity of the central magnetic field of a segmented annular iron yoke includes: S101. Obtain the basic physical parameters of the superconducting magnet.

[0023] Among them, the physical fundamental parameters refer to the key parameters characterizing the physical properties of superconducting magnets and iron yokes, including geometric parameters, electromagnetic parameters, material parameters, and iron yoke constraints.

[0024] In this embodiment, the annular segmented iron yoke center magnetic field uniformity optimization device receives externally input parameters through a parameter input module. The geometric parameters include the coil inner diameter. , outer diameter Height H, electromagnetic parameters including current density J, free permeability Material parameters include the saturation magnetic induction of ferromagnetic materials. Relative permeability and material density The iron yoke constraint includes the number of iron yokes on one side. Maximum width of the yoke Maximum depth of iron yoke and the gap range of the yoke coil [ , ].

[0025] As an example, the parameters obtained by the device include an inner diameter of 80 mm, an outer diameter of 140 mm, a current density of 150 A / mm², and a saturation magnetic induction intensity of 2.1 T for electrical pure iron.

[0026] Based on the above steps, the multi-physics fundamental parameters of the superconducting magnet can be obtained, which can provide complete and reliable basic input conditions for subsequent model building, magnetic field calculation and parameter optimization.

[0027] S102. Based on the physical parameters, establish a two-dimensional axisymmetric calculation model, determine the radial and axial calculation ranges of the covering coil, yoke, and magnetic field attenuation region, and generate a two-dimensional grid coordinate matrix.

[0028] Among them, the two-dimensional axisymmetric computational model refers to a computational model that simplifies the three-dimensional magnetic circuit problem into a two-dimensional planar problem by utilizing the axisymmetric characteristics of the structure and magnetic field distribution of the superconducting magnet, thereby reducing computational complexity.

[0029] In this embodiment, the annular segmented yoke center magnetic field uniformity optimization device first determines the spatial occupancy of the coil based on the acquired coil geometric parameters. Combining the maximum depth and maximum width of the yoke in the yoke design constraints, it delineates the radial and axial calculation boundaries that include the coil, the yoke installation area, and the effective attenuation range of the magnetic field. Then, based on the magnetic field calculation accuracy requirements, it flexibly sets the number of radial and axial grid points and calculates the grid spacing through equal or non-equal discretization. Finally, it generates a two-dimensional grid coordinate matrix covering the entire calculation area, with each grid point uniquely corresponding to a physical location in space.

[0030] It should be noted that the calculation range should be defined in a way that balances calculation accuracy and efficiency. The grid density can be flexibly adjusted according to the magnetic field gradient of different regions. In regions with a larger magnetic field gradient, the grid can be appropriately densified.

[0031] Based on the above steps, the continuous physical space can be discretized into discrete nodes that facilitate numerical calculation, providing a carrier for the accurate solution of the magnetic field distribution.

[0032] S103. Based on the Biot-Savart law and axisymmetric characteristics, the initial static magnetic field generated by the superconducting coil in space is calculated using a two-dimensional grid coordinate matrix.

[0033] Among them, the Biot-Savart law is a fundamental electromagnetic law describing the magnetic field generated by a current element in space, and can be used to derive the magnetic field distribution generated by a superconducting coil.

[0034] In this embodiment, the annular segmented iron yoke center magnetic field uniformity optimization device is based on the Biot-Savart law and the axisymmetric characteristics of the magnet. It uses an analytical method to accurately calculate the magnetic field on the axis and derives the magnetic field value by combining the contribution of the inner and outer diameters of the coil to the magnetic field. For the magnetic field outside the axis, an approximate calculation model is used, and the characteristics of the magnetic field change with spatial position are described by introducing axial decay function and radial growth function. At the same time, an end effect correction factor can be introduced according to actual needs to correct the magnetic field deviation caused by uneven current distribution at the coil end. Finally, the initial static magnetic field value corresponding to each grid point is calculated by combining the two-dimensional grid coordinate matrix.

[0035] Based on the above steps, the initial magnetic field distribution of the superconducting coil in space can be obtained comprehensively and accurately, providing a benchmark reference for subsequent optimization of the iron yoke parameters.

[0036] S104. Construct a multi-parameter optimization problem for a circular iron yoke, and use a genetic algorithm to perform a global parameter search to obtain the optimal parameters for the iron yoke.

[0037] Among them, the optimized parameters of the iron yoke refer to the optimized position, width, depth, and gap parameters of the iron yoke, which are the core variables for achieving magnetic field uniformity optimization.

[0038] In this embodiment, the annular segmented iron yoke central magnetic field uniformity optimization device first defines the optimization variables of the iron yoke, including the position, width, depth, and gap parameters of each iron yoke within the optimization range. Simultaneously, based on magnet structure constraints and manufacturing process requirements, the boundary ranges of each optimization variable are set. Next, an objective function is constructed that comprehensively considers magnetic field uniformity, central field stability, and constraint satisfaction. The weight coefficients in the objective function can be flexibly adjusted according to actual optimization needs. Subsequently, constraints related to the iron yoke layout are set, including sequence constraints, spacing constraints, and boundary constraints, to ensure that the optimization results conform to the physical laws of the magnetic circuit. Finally, the core parameters of the genetic algorithm are configured, including population size, maximum number of generations, crossover probability, mutation probability, and convergence tolerance. The algorithm traverses the optimization space through its global search characteristics and outputs iron yoke optimization parameters that satisfy the objective function requirements.

[0039] Based on the above steps, the limitations of traditional manual experience-based adjustments can be overcome, and the globally optimal combination of yoke parameters can be found efficiently, improving optimization efficiency and effectiveness.

[0040] S105. Based on the magnetic dipole theory and the saturation characteristics of ferromagnetic materials, a correction model for the magnetic field of the iron yoke is established by combining the optimized parameters of the iron yoke. The additional magnetic field generated by the iron yoke is calculated, and the additional magnetic field is superimposed with the initial static magnetic field to obtain the total magnetic field strength.

[0041] The additional magnetic field refers to the magnetic field generated by the iron yoke itself after it has been magnetized under the action of the initial static magnetic field, which is used to correct the distribution of the initial magnetic field.

[0042] In this embodiment, the annular segmented iron yoke central magnetic field uniformity optimization device first determines the spatial position and geometric dimensions of the iron yoke based on the iron yoke optimization parameters, calculates the background magnetic field strength at the location of the iron yoke in conjunction with the initial static magnetic field, and then calculates the effective magnetization of the iron yoke in conjunction with the saturation characteristics of the ferromagnetic material. Subsequently, based on the geometric parameters of the iron yoke, its volume and magnetic moment are calculated, and the basic additional magnetic field generated by the iron yoke at each grid point in space is derived using the magnetic dipole theory. At the same time, a geometric attenuation factor is introduced to correct the influence of the finite size of the iron yoke on the magnetic field attenuation characteristics, thus obtaining the final additional magnetic field. Finally, the additional magnetic fields of each iron yoke are combined with the initial static magnetic field of the superconducting coil according to the principle of vector superposition to obtain the spatial distribution of the total magnetic field strength.

[0043] Based on the above steps, the magnetic field uniformity in the central region can be improved through the magnetic field correction effect of the iron yoke.

[0044] Based on the above technical solutions, the global optimal improvement of the uniformity of the central magnetic field of the superconducting magnet can be achieved, while ensuring the stability of the central magnetic field, significantly improving design efficiency and shortening the design cycle.

[0045] In one possible implementation of the embodiments of this application, combined with Figure 1 ,like Figure 2As shown, the above S102 can be specifically implemented through the following S201, S202 and S203, which are explained in detail below: S201. Based on geometric parameters and yoke constraints, determine the radial and axial calculation boundaries of the covering coil, yoke, and magnetic field attenuation region.

[0046] The computational boundary refers to the radial and axial limit positions that define the spatial range of magnetic field numerical computation, and is used to clarify the effective area for mesh generation.

[0047] In this embodiment, the coil outer diameter is extracted from the geometric parameters by the annular segmented iron yoke center magnetic field uniformity optimization device. The coil height H and the maximum depth of the yoke in the yoke constraint. Set the radial calculation boundary as [ , ], outer diameter of the coil With the maximum depth of the iron yoke The sum of the boundary effect regions, with the axial calculation boundary set as [ , ], which includes the entire coil and the end magnetic field attenuation region.

[0048] As an example, with a coil outer diameter of 140 mm and a maximum yoke depth of 10 mm, the radial boundary is determined to be [0 mm, 200 mm] and the axial boundary to be [-200 mm, 200 mm].

[0049] Based on the above steps, the effective spatial range for magnetic field calculation can be clearly defined, providing a basis for subsequent grid generation.

[0050] S202. Set the number of radial and axial grid points and calculate the grid spacing.

[0051] Among them, the grid spacing refers to the radial or axial distance between two adjacent grid points, which determines the fineness of grid discretization.

[0052] In this embodiment of the application, the number of radial grid points is set. With axial grid point count Calculate the radial grid spacing and the axial grid spacing.

[0053] Optionally, the radial grid spacing is calculated according to the following formula:

[0054] And / or, the axial grid spacing is calculated to satisfy the following formula:

[0055] in, Radial grid spacing, This represents the axial grid spacing.

[0056] As an example, device settings =200、 =400, combined with the radial boundary [0mm, 200mm], the calculation yields... 1mm, axial boundary [-200mm, 200mm] calculated 1mm.

[0057] Based on the above steps, a uniform grid discrete interval can be obtained, providing a quantization standard for coordinate generation.

[0058] S203. Generate the coordinates of each grid point based on the grid spacing and construct a two-dimensional grid coordinate matrix.

[0059] The two-dimensional grid coordinate matrix is ​​a matrix composed of the radial and axial coordinates of all grid points, used to map the physical location within the computational region.

[0060] In this embodiment of the application, the annular segmented iron yoke center magnetic field uniformity optimization device is based on the calculated... and Calculate each radial coordinate and each axial coordinate, and then construct two-dimensional mesh coordinate matrices R and Z. Each element in the matrix corresponds to a unique physical location in space. ).

[0061] Optionally, the radial coordinates are calculated to satisfy the following formula:

[0062] And / or, calculate the axial coordinates to satisfy the following formula:

[0063] in, , .

[0064] As an example, the device is based on =1mm =1mm, generate radial coordinates 0mm, 1mm, ..., 200mm, axial coordinates -200mm, -199mm, ..., 200mm, and construct a 200×400 two-dimensional grid coordinate matrix.

[0065] Based on the above steps, the continuous physical space is discretized into discrete nodes, providing a solution carrier for subsequent magnetic field numerical calculations.

[0066] Based on the above technical solution, by defining the calculation boundary, accurately calculating the grid spacing, and constructing a coordinate matrix, the calculation space of the superconducting magnet's magnetic field is reasonably discretized, ensuring both calculation accuracy and efficiency.

[0067] In one possible implementation of the embodiments of this application, combined with Figure 1 ,like Figure 3 As shown, the above S103 can be specifically implemented through the following S301, S302, S303 and S304, which are explained in detail below: S301. The magnetic field distribution on the shaft is calculated analytically based on the contribution of the inner and outer diameters of the coil.

[0068] Among them, the on-axis magnetic field refers to the magnetic induction intensity at each spatial point on the central axis (z-axis) of the superconducting coil.

[0069] In this embodiment, the annular segmented iron yoke center magnetic field uniformity optimization device is based on the Biot-Savart law and uses an analytical method to calculate the magnetic field distribution on the axis.

[0070] Optionally, the magnetic field distribution on the axis can be calculated analytically, satisfying the following formula:

[0071] in, The magnetic field distribution on the axis, The coil height is half (H / 2). The outer radius of the coil ( / 2), The inner radius of the coil ( / 2), z is the axial coordinate of a point on the axis.

[0072] As an example, device input =40mm =70mm = H / m, the magnetic field at z=0 on the axis is calculated to be 1.48T.

[0073] Based on the above steps, the precise distribution of the magnetic field on the axis can be obtained quickly.

[0074] S302. The external magnetic field is approximated by the exponential decay model.

[0075] The external magnetic field refers to the magnetic induction intensity at a spatial point that deviates from the central axis of the coil (not the z-axis).

[0076] In this embodiment of the application, the distribution of the external magnetic field is calculated based on the on-axis magnetic field using an exponential decay model.

[0077] Optionally, the external magnetic field distribution can be calculated using an exponential decay model, satisfying the following formula:

[0078] in, For the distribution of the external magnetic field, For axial attenuation function, , It is a radial growth function. .

[0079] As an example, the external magnetic field at r=10mm and z=0 was calculated to be 1.24T.

[0080] Based on the above steps, the magnetic field distribution in the entire space can be obtained efficiently, greatly reducing the computational complexity.

[0081] S303. An end effect correction factor is introduced to correct the magnetic field deviation at the coil end.

[0082] Among them, the end effect refers to the deviation in magnetic field calculation caused by uneven current distribution at the coil ends.

[0083] In this embodiment, an end effect correction factor is introduced. , , This is the end effect coefficient, used to correct the magnetic field at the coil ends.

[0084] Based on the above steps, the magnetic field calculation deviation at the coil end can be compensated, thereby improving the accuracy of the magnetic field calculation in the entire space.

[0085] S304. Based on the two-dimensional grid coordinate matrix, calculate the average magnetic field of the central region to obtain the initial static magnetic field.

[0086] The central region refers to the core working region of the superconducting magnet, i.e., R ≤ Z≤ ( , (The boundary parameter of the central region) is defined as a small cylindrical region surrounding the center of the magnet.

[0087] In this embodiment, the annular segmented iron yoke central magnetic field uniformity optimization device traverses all grid points in the central region of the two-dimensional grid coordinate matrix to calculate the central magnetic field strength and uniformity.

[0088] Optionally, the calculation of the central magnetic field strength satisfies the following formula:

[0089] And / or, the uniformity of the central magnetic field is calculated according to the following formula:

[0090] in, The central magnetic field strength, The total number of grid points in the central area. For the uniformity of the central region.

[0091] Based on the above steps, a complete initial static magnetic field distribution can be obtained, providing complete reference data for subsequent optimization of iron yoke parameters.

[0092] Based on the above technical solution, the accuracy and efficiency of magnetic field calculation are balanced, and the accurate distribution of the initial static magnetic field in the whole space is obtained quickly, providing a reliable benchmark for the optimization of the ring iron yoke parameters.

[0093] In one possible implementation of the embodiments of this application, combined with Figure 1 ,like Figure 4 As shown, the above S104 can be implemented through the following S401, S402, S403 and S404, which are explained in detail below: S401. Set the position, width, depth, and gap of each yoke as optimization variables.

[0094] Among them, the optimization variables refer to the structural parameters of the iron yoke core that affect the uniformity of the magnetic field, and need to cover spatial location and geometric size characteristics.

[0095] In this embodiment of the application, the device for optimizing the uniformity of the magnetic field at the center of the annular segmented iron yoke defines a variable vector. Where Nb is the number of iron yokes on one side. For the position of the iron yoke, For width, For depth, To determine the gap with the coil, and simultaneously set the boundaries of each variable according to the yoke constraint, ∈[ , ]、 ∈[ , ]、 ∈[ , ]、 ∈[ , ].

[0096] Based on the above steps, the core objects to be optimized can be identified, and the scope of multi-parameter collaborative optimization can be defined.

[0097] S402. Construct an objective function that includes magnetic field inhomogeneity, maximum relative deviation, central field change rate, and constraint violation penalty term.

[0098] The objective function is a comprehensive evaluation index for measuring the optimization effect and is used to guide the algorithm to search for the optimal combination of parameters.

[0099] In this embodiment, the objective function for optimizing the uniformity of the central magnetic field of the annular segmented iron yoke satisfies the following formula:

[0100] in, For magnetic field inhomogeneity, std indicates standard deviation calculation. For the maximum relative deviation, , For the rate of change of the central field, , To optimize the magnetic field strength at the iteration center, Let P be the initial central magnetic field strength, and P be the constraint violation penalty term. As uniformity weight, The maximum deviation weight, As the central field stability weight, The weight of the penalty item.

[0101] Based on the above steps, a multi-objective collaborative evaluation standard can be established to avoid performance imbalance caused by single-objective optimization.

[0102] S403. Set yoke sequence constraints, spacing constraints, and boundary constraints.

[0103] Among them, the constraints are the limiting conditions that ensure the optimization results conform to physical laws and engineering realities.

[0104] In this embodiment, the annular segmented iron yoke central magnetic field uniformity optimization device is configured with three types of constraints: sequential constraints. (The yoke is sequentially placed towards the coil end along the axial direction), spacing constraint ≥( / 2+ / 2)+ ( Minimum safety distance) and boundary constraints (the yoke does not exceed the calculation area and does not overlap with the coil).

[0105] Based on the above steps, physically infeasible parameter combinations can be eliminated, improving the engineering applicability of the optimization results.

[0106] S404. Configure the population size, maximum number of generations, crossover probability, mutation probability, and convergence tolerance of the genetic algorithm. Perform a global search using the genetic algorithm and output the yoke optimization parameters.

[0107] Among them, the parameters of the genetic algorithm are the key settings that affect the search efficiency and the quality of the optimal solution, and both global exploration and local convergence must be taken into account.

[0108] In this embodiment of the application, the population size of the genetic algorithm is configured. (Number of chromosomes per generation), maximum number of generations (Maximum number of evolutions), crossover probability (Chromosomal crossover probability), mutation probability (Gene mutation probability), convergence tolerance (Fitness improvement threshold), then using the optimization variable as the gene and the objective function as the fitness, iteratively search through selection, crossover, and mutation operations. When the maximum number of generations is reached or the fitness is less than the convergence tolerance, the iron yoke optimization parameters are output.

[0109] It should be noted that for two iron yokes on one side, there are a total of 8 genes, which make up one chromosome.

[0110] As an example, setting =50、 =100、 =0.8、 =0.05、 = After iteration, the output parameters are the position, width, depth, and gap of the yoke.

[0111] Based on the above steps, the limitations of human experience can be overcome, and the globally optimal combination of iron yoke parameters can be found efficiently.

[0112] Based on the above technical solution, by clarifying the optimization variables, constructing a multi-objective function, setting physical constraints, and configuring the optimization algorithm, the systematic collaborative optimization of the toroidal yoke parameters was achieved. This not only ensured the physical feasibility and engineering practicality of the optimization results, but also avoided local optima through the global search characteristics of the genetic algorithm, significantly improving the optimization efficiency and effect of the uniformity of the central magnetic field of the superconducting magnet.

[0113] In one possible implementation of the embodiments of this application, combined with Figure 1 ,like Figure 5 As shown, the above S105 can be implemented through the following S501, S502 and S503, which are explained in detail below: S501. Based on the optimized parameters of the iron yoke, calculate the effective magnetization and volume of the iron yoke.

[0114] Among them, the effective magnetization intensity is the actual magnetization intensity after considering the saturation characteristics of ferromagnetic materials, and the volume is the geometric space occupied by the annular segmented iron yoke.

[0115] In this embodiment, the background magnetic field strength of the iron yoke is first determined based on the optimized parameters of the iron yoke, the magnetic field strength is calculated based on the background magnetic field, the saturation magnetization is calculated based on the saturation magnetic induction intensity of electrical pure iron, and the effective magnetization is calculated based on the obtained magnetic field strength and saturation magnetization intensity; the volume is calculated based on the geometric parameters of the iron yoke.

[0116] Optionally, the background magnetic field strength satisfies the following formula:

[0117] And / or, the magnetic field strength calculated based on the background magnetic field satisfies the following formula:

[0118] And / or, the saturation magnetization intensity is calculated based on the saturation magnetic induction intensity of electrical pure iron, satisfying the following formula:

[0119] And / or, the effective magnetization is calculated based on the obtained magnetic field strength and saturation magnetization, satisfying the following formula:

[0120] And / or, the volume calculated based on the geometric parameters of the yoke satisfies the following formula:

[0121] in, The background magnetic field strength, The radial position of the yoke center. The axial position of the yoke center. The magnetic field strength, The saturation magnetization is For effective magnetization, For volume, The outer radius of the iron yoke, Let be the inner radius of the yoke. = +c, The outer radius of the coil, = +d, where w is the width of the yoke.

[0122] Based on the above steps, the core fundamental parameters of iron yoke magnetization can be obtained, providing reliable input for magnetic moment calculation.

[0123] S502. The magnetic moment of the iron yoke is calculated based on the effective magnetization and volume, and the additional magnetic field is obtained by combining the magnetic dipole theory.

[0124] Among them, the magnetic moment is a physical quantity that characterizes the strength of the magnetization of the iron yoke, and the additional magnetic field is the correction magnetic field generated in space after the iron yoke is magnetized.

[0125] In this embodiment, the magnetic moment m of the iron yoke is calculated by multiplying the effective magnetization by the volume; the coordinates of the observation point are calculated ( , ) and the coordinates of the yoke center The spatial distance between the observation point and the yoke center is calculated; the direction cosine is calculated based on the axial and radial differences between the observation point and the yoke center, as well as the spatial distance; the additional magnetic field at the observation point is calculated based on the magnetic moment, spatial distance, and direction cosine.

[0126] Optional, calculate the coordinates of the observation point ( , ) and the coordinates of the yoke center The spatial distance between them satisfies the following formula:

[0127] And / or, based on the axial difference, radial difference, and spatial distance between the observation point and the center of the yoke, the direction cosine is calculated to satisfy the following formula:

[0128] And / or, based on the magnetic moment, spatial distance, and direction cosine, the additional magnetic field at the observation point is calculated to satisfy the following formula:

[0129] in, The additional magnetic field is represented by m, where m is the magnetic moment. Here, denoted by 'direction cosine', and 'dist' represents the spatial distance.

[0130] Based on the above steps, the additional magnetic field generated by the iron yoke can be accurately calculated, providing core data for magnetic field correction.

[0131] S503. Introduce a geometric attenuation factor to superimpose the additional magnetic field of each yoke with the initial static magnetic field to obtain the total magnetic field strength.

[0132] Among them, the geometric attenuation factor is a coefficient that corrects the approximate deviation of the magnetic dipole caused by the finite size of the iron yoke, and is used to improve the accuracy of magnetic field calculation.

[0133] In this embodiment, a geometrical attenuation factor is introduced. ,in, , The attenuation width coefficient is used; based on the geometric attenuation factor, an additional magnetic field is superimposed on the initial static magnetic field to obtain the total magnetic field strength.

[0134] Optionally, an additional magnetic field is superimposed on the initial static magnetic field to obtain the total magnetic field strength, which satisfies the following formula:

[0135] in, The axial magnetic field component at any point (r, z) in space is calculated using the same method as... same.

[0136] Based on the above steps, the magnetic field calculation deviation can be corrected, and an accurate total magnetic field distribution can be obtained.

[0137] Based on the above technical solution, the initial static magnetic field was corrected by accurately calculating the magnetization parameters of the iron yoke, solving for the additional magnetic field, and introducing correction superposition. This not only ensured the accuracy of the magnetic field calculation but also effectively improved the uniformity of the magnetic field at the center of the superconducting magnet.

[0138] In one possible implementation, combining Figure 1 ,like Figure 6 As shown, following S105 above, the method for optimizing the uniformity of the central magnetic field of the annular segmented iron yoke provided in this application embodiment further includes the following S601 and S602: S601. Calculate the uniformity improvement rate based on the inhomogeneity of the initial static magnetic field and the inhomogeneity of the total magnetic field.

[0139] Among them, the uniformity improvement rate is the core indicator for measuring the optimization effect of magnetic field uniformity, which is used to quantify the degree of improvement of the total magnetic field relative to the initial static magnetic field.

[0140] In the embodiments of this application, the initial non-uniformity and the optimized non-uniformity are calculated respectively, and then the uniformity improvement rate is calculated based on the initial non-uniformity and the optimized non-uniformity.

[0141] Optionally, the uniformity improvement rate is calculated based on the initial non-uniformity and the optimized non-uniformity, satisfying the following formula:

[0142] in, For uniformity improvement rate, For the initial non-uniformity, This is for the optimized non-uniformity.

[0143] It should be noted that the non-uniformity calculation must be limited to the same central area to ensure that the comparison benchmark is consistent.

[0144] Based on the above steps, the optimization effect can be quantified.

[0145] S602. Verify whether the position distribution, spacing, and gap between the yoke and the coil meet the preset constraint requirements.

[0146] Among them, the pre-set constraints are the premise for ensuring the physical feasibility of the yoke, including positional order, spacing safety and gap adaptation constraints.

[0147] In this embodiment, the annular segmented iron yoke central magnetic field uniformity optimization device sequentially verifies whether the optimized parameters satisfy the three types of constraints in S403.

[0148] It should be noted that if the constraint verification fails, it is necessary to return to S104 for re-optimization to ensure that the results conform to the actual engineering situation.

[0149] Based on the above steps, optimization results that are physically infeasible can be eliminated, ensuring the engineering practicality of the iron yoke layout.

[0150] Based on the above technical solution, by quantifying the uniformity improvement effect and verifying the compliance of the iron yoke constraint, the closed loop of the optimization process is improved. This not only intuitively reflects the optimization value of the method, but also ensures the physical feasibility of the optimization results, further guaranteeing the effectiveness and engineering applicability of the method in this application.

[0151] It should be noted that, to more clearly present the optimization effects and implementation process of this solution, the following is combined with... Figures 7 to 11 The application details the experimental data and uses the following initial conditions: inner diameter of coil 80mm, outer diameter 140mm, height 200mm, current density 150A / mm², number of yokes on one side 2, maximum axial width of yoke 100mm, maximum depth of 10mm, and gap range between yoke and coil [0,5]mm. The material used is electrical pure iron with saturation magnetic induction intensity of 2.1T and relative permeability of 500. The uniformity evaluation area is a cylindrical area with a height of 20mm and a radius of 10mm. Figure 7 The spatial distribution of the magnetic field in the radial (0-200mm) and axial (-200mm to 200mm) directions is shown when the initial central field is 4.97919. Figure 8 To optimize the uniformity distribution of the central region (a cylindrical region with a height of 20 mm and a radius of 10 mm), the uniformity fluctuation range is -0.256% to 0.126%. Figure 9 The specific geometric parameters of the two iron yokes on one side (a total of four bosses) are defined. Among them, the center coordinate of boss 1 is z=60.0mm, axial length is 20.0mm, radial depth is 10.0mm, gap is 3.9mm, inner radius is 73.9mm, and outer radius is 83.9mm. The center coordinate of boss 2 is z=140.0mm, axial length is 20.0mm, radial depth is 10.0mm, gap is 2.0mm, inner radius is 72.0mm, and outer radius is 82.0mm. Bosses 3 and 4 are arranged symmetrically with bosses 1 and 2 about the center of the magnet, respectively. Figure 10 The central field was stabilized at 4.99925, and the uniformity of the magnetic field spatial distribution was significantly improved. Figure 11 The uniformity fluctuation range is optimized to -0.236% to 0.116%. Quantitative calculations show that this application achieves a uniformity improvement rate of 7.8% and a central field change rate of only 0.4%, which fully demonstrates that it can significantly improve the magnetic field uniformity in the central region of the superconducting magnet while maximizing the stability of the central magnetic field. The optimization effect is significant and has engineering applicability.

[0152] The above primarily describes the solutions of the embodiments of this application from the perspective of device implementation. It is understood that each device, such as the annular segmented iron yoke central magnetic field uniformity optimization device, includes at least one of the hardware structures and software modules corresponding to each function in order to achieve the above-mentioned functions. Those skilled in the art should readily recognize that, in conjunction with the units and algorithm steps of the various examples described in the embodiments disclosed herein, this application can be implemented in hardware or a combination of hardware and computer software. Whether a function is implemented in hardware or by computer software driving hardware depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0153] This application embodiment can divide the annular segmented iron yoke central magnetic field uniformity optimization device into functional units according to the above method example. For example, each function can be divided into separate functional units, or two or more functions can be integrated into one processing unit. The integrated unit can be implemented in hardware or software functional units. It should be noted that the unit division in this application embodiment is illustrative and only represents one logical functional division; other division methods may be used in actual implementation.

[0154] When using integrated units, Figure 12 A possible structural schematic diagram of the annular segmented iron yoke center magnetic field uniformity optimization device (denoted as annular segmented iron yoke center magnetic field uniformity optimization device 120) involved in the above embodiments is shown. The annular segmented iron yoke center magnetic field uniformity optimization device 120 includes a processing unit 1201 and a communication unit 1202, and may also include a storage unit 1203. Figure 12 The schematic diagram shown can be used to illustrate the structure of the annular segmented iron yoke central magnetic field uniformity optimization device involved in the above embodiments.

[0155] when Figure 12 The schematic diagram shown illustrates the structure of the annular segmented iron yoke central magnetic field uniformity optimization device involved in the above embodiments. The processing unit 1201 is used to control and manage the operation of the annular segmented iron yoke central magnetic field uniformity optimization device, the communication unit 1202 is used for the annular segmented iron yoke central magnetic field uniformity optimization device to communicate with other devices, and the storage unit 1203 is used to store the program code and data of the annular segmented iron yoke central magnetic field uniformity optimization device.

[0156] For example, communication unit 1202 is used to acquire the physical fundamental parameters of the superconducting magnet; the physical fundamental parameters include geometric parameters, electromagnetic parameters, material parameters, and iron yoke constraints; Processing unit 1201 is used to establish a two-dimensional axisymmetric calculation model based on physical fundamental parameters, determine the radial and axial calculation ranges of the covering coil, yoke, and magnetic field attenuation region, and generate a two-dimensional grid coordinate matrix; based on the Biot-Savart law and axisymmetric characteristics, it uses the two-dimensional grid coordinate matrix to calculate the initial static magnetic field generated by the superconducting coil in space; it constructs a multi-parameter optimization problem for the ring yoke, uses a genetic algorithm to perform a global parameter search, and obtains the optimized parameters of the yoke; based on the magnetic dipole theory and the saturation characteristics of ferromagnetic materials, it combines the optimized parameters of the yoke to establish a correction model of the magnetic field on the yoke, calculates the additional magnetic field generated by the yoke, and superimposes the additional magnetic field with the initial static magnetic field to obtain the total magnetic field strength.

[0157] In one possible implementation, the geometric parameters include the inner diameter, outer diameter, and height of the coil; the electromagnetic parameters include the current density and vacuum permeability; the material parameters include the saturation magnetic induction intensity, relative permeability, and material density of electrical pure iron; and the yoke constraints include the number of yokes on one side, the maximum width of the yoke, the maximum depth of the yoke, and the range of the gap between the yoke and the coil.

[0158] In one possible implementation, the processing unit 1201 is further configured to calculate the uniformity improvement rate based on the non-uniformity of the initial static magnetic field and the non-uniformity of the total magnetic field; and to verify whether the position distribution, spacing, and gap between the yoke and the coil meet the preset constraint requirements.

[0159] In one possible implementation, the processing unit 1201 is further configured to establish a two-dimensional axisymmetric calculation model based on physical parameters, determine the radial and axial calculation ranges of the covering coil, yoke, and magnetic field attenuation region, and generate a two-dimensional mesh coordinate matrix, including: determining the radial and axial calculation boundaries of the covering coil, yoke, and magnetic field attenuation region based on geometric parameters and yoke constraints; setting the number of radial and axial mesh points and calculating the mesh spacing; generating the coordinates of each mesh point based on the mesh spacing and constructing a two-dimensional mesh coordinate matrix.

[0160] In one possible implementation, the processing unit 1201 is further configured to calculate the initial static magnetic field generated by the superconducting coil in space using a two-dimensional grid coordinate matrix based on the Biot-Savart law and axisymmetric characteristics. This includes: calculating the axial magnetic field distribution using an analytical method based on the contributions of the coil's inner and outer diameters; approximating the outer magnetic field using an exponential decay model; characterizing the axial decay and radial growth saturation characteristics of the magnetic field using an axial decay function and a radial growth function; introducing an end effect correction factor to correct the magnetic field deviation at the coil ends; and calculating the average magnetic field in the central region based on the two-dimensional grid coordinate matrix to obtain the initial static magnetic field.

[0161] In one possible implementation, the processing unit 1201 is further configured to construct a multi-parameter optimization problem for a ring yoke, and to perform a global parameter search using a genetic algorithm to obtain the yoke optimization parameters, including: setting the position, width, depth, and gap of each yoke as optimization variables; constructing an objective function containing magnetic field inhomogeneity, maximum relative deviation, central field change rate, and constraint violation penalty terms; setting yoke order constraints, spacing constraints, and boundary constraints; configuring the population size, maximum number of generations, crossover probability, mutation probability, and convergence tolerance of the genetic algorithm; and performing a global search using the genetic algorithm to output the yoke optimization parameters.

[0162] In one possible implementation, the processing unit 1201 is further configured to establish a correction model of the magnetic field by the iron yoke based on the magnetic dipole theory and the saturation characteristics of ferromagnetic materials, combined with the iron yoke optimization parameters, calculate the additional magnetic field generated by the iron yoke, and superimpose the additional magnetic field with the initial static magnetic field to obtain the total magnetic field strength. This includes: calculating the effective magnetization and volume of the iron yoke based on the iron yoke optimization parameters; calculating the magnetic moment of the iron yoke based on the effective magnetization and volume, and obtaining the additional magnetic field by combining the magnetic dipole theory; introducing a geometric attenuation factor, and superimposing the additional magnetic fields of each iron yoke with the initial static magnetic field to obtain the total magnetic field strength.

[0163] In one possible implementation, the processing unit 1201 is further configured to calculate the magnetic moment of the yoke based on the effective magnetization and volume, and obtain the additional magnetic field by combining the magnetic dipole theory, including: calculating the spatial distance between the coordinates of the observation point and the coordinates of the yoke center; calculating the direction cosine based on the axial difference, radial difference and spatial distance between the observation point and the yoke center; and calculating the additional magnetic field at the observation point based on the magnetic moment, spatial distance and direction cosine.

[0164] In one possible implementation, the additional magnetic field at the observation point is calculated based on the magnetic moment, spatial distance, and direction cosine, satisfying the following formula:

[0165] in, To add a magnetic field, where is the free permeability and m is the magnetic moment. Here, denoted by 'direction cosine', and 'dist' represents the spatial distance.

[0166] The processing unit 1201 can be a processor or a controller, and the communication unit 1202 can be a communication interface, transceiver, transceiver circuit, transceiver device, etc. The term "communication interface" is a general term and may include one or more interfaces. The storage unit 1203 can be a memory. When the annular segmented iron yoke central magnetic field uniformity optimization device 120 is a chip, the processing unit 1201 can be a processor or a controller, and the communication unit 1202 can be an input interface and / or an output interface, pins, or circuits, etc. The storage unit 1203 can be a storage unit within the chip (e.g., a register, cache, etc.) or a storage unit located outside the chip (e.g., read-only memory (ROM), random access memory (RAM, etc.).

[0167] The communication unit can also be called a transceiver unit. The antenna and control circuit with transceiver functions in the ring segmented iron yoke center magnetic field uniformity optimization device 120 can be considered as the communication unit 1202 of the ring segmented iron yoke center magnetic field uniformity optimization device 120, and the processor with processing functions can be considered as the processing unit 1201 of the ring segmented iron yoke center magnetic field uniformity optimization device 120. Optionally, the device in the communication unit 1202 used to implement the receiving function can be considered as the communication unit, which is used to execute the receiving steps in the embodiments of this application. The communication unit can be a receiver, a receiver circuit, etc. The device in the communication unit 1202 used to implement the transmitting function can be considered as the transmitting unit, which is used to execute the transmitting steps in the embodiments of this application. The transmitting unit can be a transmitter, a transmitter, a transmitting circuit, etc.

[0168] Figure 12 If the integrated units in the process are implemented as software functional modules and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solutions of the embodiments of this application, in essence, or the parts that contribute to the prior art, or all or part of the technical solutions, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) or processor to execute all or part of the steps of the methods described in the various embodiments of this application. Storage media for storing computer software products include various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory, random access memory, magnetic disks, or optical disks.

[0169] Figure 12 The units in the process can also be called modules; for example, a processing unit can be called a processing module.

[0170] In the above embodiments, implementation can be achieved, in whole or in part, through software, hardware, firmware, or any combination thereof. When implemented using software programs, implementation can be, in whole or in part, in the form of a computer program product. This computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, all or part of the processes or functions described in the embodiments of this application are generated. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions can be stored in a computer-readable storage medium or transmitted from one computer-readable storage medium to another. For example, computer instructions can be transmitted from one website, computer, server, or data center to another website, computer, server, or data center via wired (e.g., coaxial cable, fiber optic, digital subscriber line (DSL)) or wireless (e.g., infrared, wireless, microwave, etc.) means. The computer-readable storage medium can be any available medium accessible to a computer or a data storage device containing one or more servers, data centers, etc., that can be integrated with the medium. The available media can be magnetic media (e.g., floppy disks, hard disks, magnetic tapes), optical media (e.g., DVDs), or semiconductor media (e.g., solid-state disks (SSDs)).

[0171] Although this application has been described herein in conjunction with various embodiments, those skilled in the art, by reviewing the accompanying drawings, disclosure, and appended claims, will understand and implement other variations of the disclosed embodiments in carrying out the claimed application. In the claims, the word "comprising" does not exclude other components or steps, and "a" or "an" does not exclude multiple instances. A single processor or other unit can implement several functions listed in the claims. While different dependent claims may recite certain measures, this does not mean that these measures cannot be combined to produce good results.

[0172] Although this application has been described in conjunction with specific features and embodiments, it is obvious that various modifications and combinations can be made thereto without departing from the spirit and scope of this application. Accordingly, this specification and drawings are merely exemplary illustrations of this application as defined by the appended claims, and are considered to cover any and all modifications, variations, combinations, or equivalents within the scope of this application. Clearly, those skilled in the art can make various alterations and modifications to this application without departing from the spirit and scope of this application. Thus, if such modifications and modifications of this application fall within the scope of the claims of this application and their equivalents, this application is also intended to include such modifications and modifications.

Claims

1. A method for optimizing the uniformity of the central magnetic field of a segmented annular iron yoke, characterized in that, include: Obtain the fundamental physical parameters of the superconducting magnet; these parameters include geometric parameters, electromagnetic parameters, material parameters, and iron yoke constraints. A two-dimensional axisymmetric calculation model is established based on the physical parameters to determine the radial and axial calculation ranges of the covering coil, yoke, and magnetic field attenuation region, and to generate a two-dimensional grid coordinate matrix. Based on the Biot-Savart law and axisymmetric properties, the initial static magnetic field generated by the superconducting coil in space is calculated using the two-dimensional grid coordinate matrix. A multi-parameter optimization problem for a circular iron yoke is constructed, and a genetic algorithm is used to perform a global parameter search to obtain the optimal iron yoke parameters. Based on the magnetic dipole theory and the saturation characteristics of ferromagnetic materials, a correction model for the magnetic field of the iron yoke is established by combining the optimized parameters of the iron yoke. The additional magnetic field generated by the iron yoke is calculated, and the additional magnetic field is superimposed with the initial static magnetic field to obtain the total magnetic field strength.

2. The method according to claim 1, characterized in that, The geometric parameters include the inner diameter, outer diameter, and height of the coil; the electromagnetic parameters include current density and vacuum permeability; the material parameters include the saturation magnetic induction intensity, relative permeability, and material density of electrical pure iron; and the yoke constraint includes the number of yokes on one side, the maximum width of the yoke, the maximum depth of the yoke, and the range of the gap between the yoke and the coil.

3. The method according to claim 1, characterized in that, After establishing a correction model for the magnetic field based on the magnetic dipole theory and the saturation characteristics of ferromagnetic materials, combined with the optimized parameters of the iron yoke, calculating the additional magnetic field generated by the iron yoke, and superimposing the additional magnetic field with the initial static magnetic field to obtain the total magnetic field distribution, the method further includes: The uniformity improvement rate is calculated based on the inhomogeneity of the initial static magnetic field and the inhomogeneity of the total magnetic field. Verify whether the position distribution, spacing, and gap between the yoke and the coil meet the preset constraint requirements.

4. The method according to claim 2, characterized in that, A two-dimensional axisymmetric calculation model is established based on the aforementioned physical parameters. The radial and axial calculation ranges of the covering coil, yoke, and magnetic field attenuation region are determined, and a two-dimensional mesh coordinate matrix is ​​generated, including: Based on the geometric parameters and the yoke constraint, the radial and axial calculation boundaries of the covering coil, the yoke, and the magnetic field attenuation region are determined. Set the number of radial and axial grid points, and calculate the grid spacing; The coordinates of each grid point are generated based on the grid spacing, and a two-dimensional grid coordinate matrix is ​​constructed.

5. The method according to claim 2, characterized in that, The calculation of the initial static magnetic field generated by the superconducting coil in space using the two-dimensional grid coordinate matrix, based on the Biot-Savart law and axisymmetric properties, includes: The magnetic field distribution on the shaft is calculated analytically based on the contribution of the inner and outer diameters of the coil. The external magnetic field is approximated by an exponential decay model; the exponential decay model characterizes the axial decay and radial growth saturation characteristics of the magnetic field through an axial decay function and a radial growth function. An end-effect correction factor is introduced to correct the magnetic field deviation at the coil ends; Based on the two-dimensional grid coordinate matrix, the average magnetic field of the central region is calculated to obtain the initial static magnetic field.

6. The method according to claim 2, characterized in that, The aforementioned multi-parameter optimization problem for constructing a circular iron yoke employs a genetic algorithm for global parameter search to obtain the optimized iron yoke parameters, including: Set the position, width, depth, and gap of each yoke as optimization variables; Construct an objective function that includes magnetic field inhomogeneity, maximum relative deviation, central field change rate, and constraint violation penalty term; Set yoke sequence constraints, spacing constraints, and boundary constraints; Configure the population size, maximum number of generations, crossover probability, mutation probability, and convergence tolerance of the genetic algorithm, perform a global search using the genetic algorithm, and output the iron yoke optimization parameters.

7. The method according to claim 2, characterized in that, Based on magnetic dipole theory and the saturation characteristics of ferromagnetic materials, a correction model for the magnetic field of the iron yoke is established using the optimized parameters of the iron yoke. The additional magnetic field generated by the iron yoke is calculated, and this additional magnetic field is superimposed with the initial static magnetic field to obtain the total magnetic field strength, including: Based on the optimized parameters of the iron yoke, the effective magnetization and volume of the iron yoke are calculated; The magnetic moment of the iron yoke is calculated based on the effective magnetization and volume, and the additional magnetic field is obtained by combining the magnetic dipole theory. By introducing a geometric attenuation factor, the additional magnetic field of each iron yoke is superimposed with the initial static magnetic field to obtain the total magnetic field strength.

8. The method according to claim 7, characterized in that, The magnetic moment of the iron yoke is calculated based on the effective magnetization and volume, and the additional magnetic field is obtained by combining the magnetic dipole theory, including: Calculate the spatial distance between the coordinates of the observation point and the coordinates of the yoke center; Calculate the direction cosine based on the axial and radial differences between the observation point and the center of the yoke, as well as the spatial distance. The additional magnetic field at the observation point is calculated based on the magnetic moment, the spatial distance, and the direction cosine.

9. The method according to claim 8, characterized in that, Based on the magnetic moment, the spatial distance, and the direction cosine, the additional magnetic field at the observation point is calculated to satisfy the following formula: in, For the additional magnetic field, Let m be the vacuum permeability, and m be the magnetic moment. Let be the direction cosine, and dist be the spatial distance.

10. A device for optimizing the uniformity of the central magnetic field of a segmented annular iron yoke, characterized in that, The device includes: a communication unit and a processing unit; The communication unit is used to acquire the basic physical parameters of the superconducting magnet; the basic physical parameters include geometric parameters, electromagnetic parameters, material parameters, and iron yoke constraints. The processing unit is used to establish a two-dimensional axisymmetric calculation model based on the physical fundamental parameters, determine the radial and axial calculation ranges of the covering coil, yoke, and magnetic field attenuation region, and generate a two-dimensional grid coordinate matrix; based on the Biot-Savart law and axisymmetric characteristics, it uses the two-dimensional grid coordinate matrix to calculate the initial static magnetic field generated by the superconducting coil in space; it constructs a multi-parameter optimization problem for the toroidal yoke, uses a genetic algorithm to perform a global parameter search, and obtains the optimized parameters for the yoke; based on the magnetic dipole theory and the saturation characteristics of ferromagnetic materials, it combines the optimized parameters for the yoke to establish a correction model for the magnetic field of the yoke, calculates the additional magnetic field generated by the yoke, and superimposes the additional magnetic field with the initial static magnetic field to obtain the total magnetic field strength.

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