CN-122021067-A - Multipole magnet design method based on expansion inverse boundary element three-dimensional optimization

CN122021067ACN 122021067 ACN122021067 ACN 122021067ACN-122021067-A

Abstract

The invention discloses a multipole magnet design method based on expansion inverse boundary element three-dimensional optimization, which relates to the technical field of superconducting magnets and comprises the steps of determining a coil distribution curved surface of a magnet according to actual requirements, carrying out grid segmentation according to the coil distribution curved surface to obtain a grid model, defining grid node current density to be solved on grid nodes of the grid model, carrying out linear scalar magnetic field superposition construction on a vector target magnetic field, carrying out optimization solving on the grid node current density through a function phi of the linear scalar magnetic field superposition construction, obtaining a multipole magnet coil structure according to distribution of the solved grid node current density, taking the magnetic field distribution of a whole three-dimensional target area as an optimization target, improving the axial magnetic field uniformity of the multipole magnet, allowing the shape of source points and field points to be freely defined, being compact and efficient, realizing higher space utilization rate and higher target magnetic field, and simultaneously being capable of considering mechanical structure design and skeleton processing convenience.

Inventors

WEI TONG
LIU WEI
LI MENG
LI CHAO
SHI XIAOBIN
ZHANG TAO
CHEN CHUAN
DING HAO
YUAN PENGTAO
MA PENG

Assignees

西安聚能超导磁体科技股份有限公司

Dates

Publication Date: 20260512
Application Date: 20260410

Claims (7)

1. The multipole magnet design method based on the three-dimensional optimization of the expansion inverse boundary element is characterized by comprising the following steps: Determining a coil distribution curved surface of the magnet according to actual requirements; grid segmentation is carried out according to the coil distribution curved surface to obtain a grid model; defining grid node current density to be solved on grid nodes of the grid model; By linear scalar magnetic field superposition construction of vector target magnetic fields: optimizing and solving the grid node current density by a function phi constructed by superposing the linear scalar magnetic fields; obtaining a multipole magnet coil structure according to the solved distribution of the grid node current density; and manufacturing a multipole magnet according to the multipole magnet coil structure.
2. The method of designing a multipole magnet based on extended inverse boundary element three-dimensional optimization of claim 1, wherein defining grid node current densities to be solved on grid nodes of the grid model comprises: the grid node current density is defined according to the following equation: ; Wherein, the Is the current density vector at spatial location r, N is the total number of grid nodes, N is the node number, representing the subscript of traversing all current nodes, from 1 to N, I n is the undetermined current density for the nth node, f n (r) is the current basis function corresponding to the nth node, and is a function related to spatial location r.
3. The method for designing a multipole magnet based on three-dimensional optimization of extended inverse boundary elements according to claim 2, wherein constructing by linear scalar magnetic field superposition on a vector target magnetic field comprises: The superimposed triaxial magnetic flux density is obtained through the Pioshaval law and the grid node current density and is shown in the following formula: ; ; ; Wherein, the The method comprises the steps of deducing an x-axis component of a magnetic induction intensity component at a certain point r in a space, wherein r is a position vector of a magnetic field to be calculated in the space, x, y and z are rectangular coordinate components of the field point r, x ', y', z 'are rectangular coordinate components of a source point r', mu 0 is vacuum permeability, N is the total number of grid nodes, N is a node serial number and represents subscripts of traversing all current nodes from 1 to N; is the component of the current basis vector function at the nth node in x, y and z, and is used for describing the spatial distribution form of the current at the nth node; representing the distance from a field point to a source point, namely the linear distance between the point of the magnetic field to be calculated in space and a current node; The target magnetic field distribution to be optimized is defined as any combination of three magnetic field components B x (r),B y (r),B z (r), as shown in the following formula: ; Wherein, the A, B and c are component adjusting coefficients for controlling the weights of the three magnetic field components B x 、B y 、B z in the target magnetic field, The x, y and z components of the magnetic induction intensity at the spatial point r are respectively.
4. A multipole magnet design method based on extended inverse boundary element three-dimensional optimization according to claim 3, characterized in that the optimization by the function Φ constructed by superimposing the linear scalar magnetic field is performed by the least square method.
5. The method for designing a multipole magnet based on three-dimensional optimization of extended inverse boundary elements according to claim 4, wherein the optimized function Φ is represented by the following formula: ; Wherein, the For adjusting coefficients, the importance duty ratio of the magnet inductance L, the torque M x in the direction of the magnet coil linear quantity P, x, the torque M y in the y direction and the torque M z in the z direction in the optimization process are respectively responsible for adjusting, wherein W is a weight coefficient at different positions r k ; Is a known target magnetic field distribution, The magnetic field distribution is calculated based on the current density of the grid nodes, K is the total number of the grid nodes around the magnet, and K is the serial number of the grid nodes around the magnet.
6. The method for designing a multipole magnet based on three-dimensional optimization of extended inverse boundary elements according to claim 1, wherein obtaining a multipole magnet coil structure from the distribution of the grid node current densities solved comprises: and carrying out contour line division on the obtained distribution of the grid node current density to obtain the three-dimensional coil structure of the multipolar magnet coil.
7. The method for designing a multipole magnet based on three-dimensional optimization of extended inverse boundary elements according to claim 6, wherein the manufacturing of the multipole magnet according to the multipole magnet coil structure is to manufacture a real multipole magnet coil according to the three-dimensional coil structure; And assembling the multipole magnet according to the actual multipole magnet coil.

Description

Multipole magnet design method based on expansion inverse boundary element three-dimensional optimization Technical Field The invention relates to the technical field of superconducting magnets, in particular to a multipole magnet design method based on expansion inverse boundary element three-dimensional optimization. Background The superconducting multipolar magnet is a high-precision magnetic field device developed by the low-temperature zero-resistance characteristic of a superconducting material, and a coil with a special configuration (such as saddle-shaped, spiral-shaped and cosine-shaped) is used for generating a specific distribution magnetic field of two poles, four poles, six poles and the like, and the core is used for deflection, focusing, guiding and nonlinear correction of a particle beam. Superconducting multipole magnets are core components of large high-energy physical devices such as European Large Hadron Collimators (LHCs), lanzhou heavy ion accelerators (HIRFL), shanghai synchrotron radiation light sources (SSRF), and the like. The technical evolution of the method always breaks through the field intensity limit, improves the magnetic field quality, optimizes the low-temperature stability and reduces the development of quench risk, and is one of core technologies for promoting high-energy physical research, advanced manufacturing and precise medical development. At present, superconducting multipolar magnets are all approximately designed based on infinite-length current lines, and various extension coil configurations of multipolar magnets, such as common coil magnets, block-type magnets and cosine-type magnets, have been proposed. The cosine distributed magnet is more widely adopted because of the characteristic of high magnetic field uniformity and small lorentz force accumulated on the coil. Further, the cosine-type magnets may be classified into a general cosine-type magnet, a gradient cosine (CCT) magnet, a Discrete Cosine (DCT) magnet, and a single-layer cosine (Uni-layer) magnet. However, the superconducting multipole magnets are designed based on two-dimensional approximation, and the end structures at two sides of the magnets are further approximated by different methods. Only the magnetic field quality requirements of the axial midplane of the magnet can be guaranteed. Once away from the axial midplane, the quality of the magnetic field produced by such magnets drops rapidly, resulting in severe distortion of the quality of the magnetic field at the ends of the magnet on either side. On the other hand, most coil formers are limited to cylindrical or curved cylindrical structures, limited by current design methods. And does not match well with the elliptical beam cross-section. This results in a coil that is less space efficient and it is difficult to achieve higher field strengths in the target area. Simultaneously, the framework processing and the structural design are inconvenient, and the framework processing cost is high. Disclosure of Invention The embodiment of the invention provides a multipole magnet design method based on three-dimensional optimization of an extended inverse boundary element, which is used for solving the problems that in the prior art, based on a two-dimensional approximation method, the end magnetic field quality on two sides of a magnet is seriously distorted, a coil framework is limited to a cylindrical or curved cylindrical structure, the coil is lower in space utilization rate due to the fact that the coil framework cannot be well matched with an elliptical beam section, higher field intensity is difficult to realize in a target area, inconvenience is brought to framework machining and structural design, and the framework machining cost is higher. In one aspect, the embodiment of the invention provides a multipole magnet design method based on three-dimensional optimization of an extended inverse boundary element, which comprises the following steps: Determining a coil distribution curved surface of the magnet according to actual requirements; grid segmentation is carried out according to the coil distribution curved surface to obtain a grid model; defining grid node current density to be solved on grid nodes of the grid model; By linear scalar magnetic field superposition construction of vector target magnetic fields: optimizing and solving the grid node current density by a function phi constructed by superposing the linear scalar magnetic fields; obtaining a multipole magnet coil structure according to the solved distribution of the grid node current density; and manufacturing a multipole magnet according to the multipole magnet coil structure. In one possible implementation, defining the grid node current density to be solved on the grid nodes of the grid model includes: the grid node current density is defined according to the following equation: ; Wherein, the Is the current density vector at spatial location r, N is the total number of