CN114068133B - Novel superconducting magnet coil structure and design method - Google Patents
Novel superconducting magnet coil structure and design method Download PDFInfo
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- CN114068133B CN114068133B CN202010794560.4A CN202010794560A CN114068133B CN 114068133 B CN114068133 B CN 114068133B CN 202010794560 A CN202010794560 A CN 202010794560A CN 114068133 B CN114068133 B CN 114068133B
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
- H01F6/00—Superconducting magnets; Superconducting coils
- H01F6/06—Coils, e.g. winding, insulating, terminating or casing arrangements therefor
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- G—PHYSICS
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- G06F30/00—Computer-aided design [CAD]
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- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06F—ELECTRIC DIGITAL DATA PROCESSING
- G06F30/00—Computer-aided design [CAD]
- G06F30/30—Circuit design
- G06F30/39—Circuit design at the physical level
- G06F30/394—Routing
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
- H01F41/00—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties
- H01F41/02—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties for manufacturing cores, coils, or magnets
- H01F41/04—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties for manufacturing cores, coils, or magnets for manufacturing coils
- H01F41/048—Superconductive coils
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
- H01F6/00—Superconducting magnets; Superconducting coils
- H01F6/04—Cooling
Abstract
The invention discloses a novel superconducting magnet coil structure and a design method, aiming at the problems of more coil layers at the end part of the traditional superconducting magnet coil, difficulty in heat dissipation and resin impregnation and high quench risk. The novel structure divides the solenoid coil with larger size into a plurality of layers in the radial direction, and each layer is separated by a separation plate. The partition plate is connected with the cold head for cooling the coil. When designing a coil, predetermining the position of a partition board in a wiring area, dividing the wiring area into a plurality of layers along the radial direction according to the position of the partition board, then carrying out grid division on the wiring area, determining current clusters meeting design requirements in the wiring area by adopting an optimization algorithm, and enabling each current cluster to be equivalent to a solenoid coil; and further optimizing the parameters of each solenoid coil by adopting a nonlinear programming algorithm. Compared with the traditional structure, the novel structure of the invention is easier to cool, resin is easier to permeate into the coil, the degree of freedom of design is increased, and the design requirement is easier to meet.
Description
Technical Field
The present invention relates to a superconducting magnet coil structure and a design method, and more particularly, to a novel superconducting magnet coil structure and a design method in a nuclear magnetic resonance imaging system.
Background
In a superconducting magnetic resonance imaging system, a superconducting magnet coil generating a highly uniform background field is generally composed of a plurality of coaxial solenoid coils connected in series. Typically, there is one of these coils that is much larger in size than the other coils. And the location of the coil is often at the end of the main coil former. The coil is oversized, which makes impregnation with resin and heat dissipation from the coil difficult. And the position of end coil is in the skeleton tip, is changeed in receiving the influence of heat radiation. The end coils are therefore more susceptible to quench than the other coils. This coil structure gives the magnet great instability. In order to improve the stability of the coil and reduce the loss rate of the magnet, the invention provides a novel superconducting magnet coil structure and a design algorithm aiming at the structure.
Disclosure of Invention
The purpose of the invention is as follows: the invention aims to provide a novel superconducting magnet coil structure and a design method, which are used for ensuring that a large coil can be fully radiated and resin can be fully soaked into the coil, so that the risk of coil quench is greatly reduced.
The technical scheme is as follows: in order to realize the purpose of the invention, the invention adopts the following technical scheme:
a novel superconducting magnet coil structure is characterized in that a superconducting magnet coil is formed by connecting a plurality of solenoid coils in series, the central axes of all the solenoids are overlapped, the solenoid coils with the layer number exceeding a set value N are divided into a plurality of coils with overlapped axial positions in the radial direction and are separated by using partition plates, and N is a preset positive integer.
Furthermore, the value range of N is more than or equal to 20 and less than or equal to 30.
Further, the isolation plate is a metal plate coated with an insulating layer on the surface.
Further, there are slits or holes in the partition plate that allow the resin to flow through.
Further, the division plate is connected with the magnet cold head.
A novel superconducting magnet coil design method comprises two steps, wherein the design step comprises the first step of setting the wiring area range of a main coil and a shielding coil and the magnetic field uniformity in a magnetic field uniform area, the maximum number of layers allowed by each solenoid coil, the initial thickness of an isolation plate and the size of a superconducting wire, predetermining the placement position of the isolation plate in the wiring area, dividing the wiring area into a plurality of layers along the radial direction according to the position of the isolation plate, then carrying out grid division on the wiring area, adopting an optimization algorithm to determine current clusters meeting design requirements in the wiring area, enabling each current cluster to be equivalent to one solenoid coil, determining the size, the position and the working current of each solenoid coil according to the current cluster distribution, and enabling the equivalent coils of the current clusters which are located on different layers but have the same axial position to have the same length and the same axial position; and secondly, further optimizing the parameters of each solenoid coil by adopting a nonlinear programming algorithm to obtain the coil parameters meeting the design requirements.
Further, the first step adopts a linear programming algorithm for optimization, and the second step adopts an interior point method for optimization.
Further, the first step of optimizing comprises:
(1) Determining coil design parameters and the maximum layer number N of the coil, wherein the coil design parameters comprise the size of a wiring area and the intensity B of a background field 0 Imaging area range, magnetic field uniformity e, maximum operating current I max The height h and the width w of the superconducting wire and the initial thickness delta of the isolation plate are calculated;
(2) Taking any two-dimensional plane passing through the axis of the coil, establishing a coordinate system in the plane, and setting the axis direction as Z-axis direction and the direction vertical to the Z-axis as R direction to make the inner diameter of the wiring region of the main coil be R p,min Outer diameter of R p,max Left axial coordinate of Z p,min Right axial coordinate of Z p,max The main coil wiring region is radially located at [ R ] p,min +gNh+(g-1)Δ,R p,min +g(Nh+Δ)]The area of the wiring area is determined as the position of the g-th layer of the isolation board, wherein g is a positive integer, the wiring area is radially divided into a plurality of layers according to the position of the isolation board, then rectangular grid division is carried out on each layer of the wiring area, and the total grid number is represented by M;
(3) Solving the following optimization problem with constraint conditions:
s.t.
|J m |≤J MAX
in the above formula, V 1 Representing the homogeneous field region, V, within the coil 2 Denotes the stray field region outside the coil, K1 and K2 respectively denote V 1 、V 2 Number of samples in, J m Denotes the current density, p, within the grid numbered m m Denotes the radial coordinate of the center of the grid numbered m, B max Represents the maximum value of magnetic induction intensity allowed at the sampling point outside the coil, J MAX Represents the maximum current density allowed in the wiring area, alpha, beta and gamma are self-defined parameters,
at the sampling point when the unit current density is uniformly distributed, the grids numbered m respectively
Axial magnetic induction and radial magnetic induction generated at the position;
(4) And (4) obtaining initial parameters of the coil according to the solution of the step (3).
Further, the mathematical model of the second step of optimization is as follows:
s.t.
z 1,n+1 -z 2,n ≥δ,1≤n≤C-1,n≠C p
ρ 1,n ≥R p,min ,ρ 2,n ≤R p,max ,1≤n≤C p
ρ 1,n ≥R s,min ,ρ 2,n ≤R s,max ,C p +1≤n≤C
ρ 2,n -ρ 1,n ＝wT r,n ,1≤n≤C
z 2,n -z 1,n ＝hL z,n ,1≤n≤C
z 1,v+n ＝z 1,v ,1≤n≤Γ
Δ 1 ≤ρ 1,v+n -ρ 2,v+n-1 ≤Δ 2 ,1≤n≤Γ
I≤I max
in the above formula, the symbol z 1,n 、z 2,n Respectively representing the axial coordinates, p, of the left and right ends of the coil n 1,n 、ρ 2,n Respectively representing the radial coordinates of the inner and outer ends of the coil n, z 1,1 Is the axial coordinate of the left end coil of the main coil,
is the right axial coordinate of the coil at the right end of the main coil,
is the left axial coordinate, z, of the left coil of the shield coil 2,C Is the right-hand axial coordinate, T, of the right-hand coil of the shield coil r,n 、L z,n Respectively, the number of turns and the number of layers of the coil n, delta the axial minimum spacing of the two coils,
the sample point numbered i is indicated,
respectively representing sampling points
And sampling point
The axial component of the magnetic field at (a),
showing the coil at
Amplitude of the magnetic field generated, C p Indicates the number of main coils, C indicates the total number of coils, R p,min 、R p,max Respectively representing the minimum and maximum allowable internal and external diameters, Z, of the main coil p,min 、Z p,max Respectively representing the minimum and maximum axial coordinate values, R, allowed for the main coil s,min 、R s,max Respectively representing the minimum and maximum allowable inner and outer diameters, Z, of the shield coil s,min 、Z s,max The minimum and maximum coordinate values of the axial direction allowed by the shield coil are respectively shown, I is the working current, and the coil numbers which need to be separated by the isolation plate are v to v + gamma, delta 1 、Δ 2 The minimum thickness and the maximum thickness of the separator are indicated.
Has the advantages that: compared with the prior art, the design method has the advantages that: the large-size coil is divided into a plurality of layers which are connected in series in the radial direction, the partition plate is added in the middle of each layer, the partition plate is connected with the cold head, the heat dissipation inside the coil can be increased, gaps are formed in the partition plate, the fact that resin is fully permeated into the coil can be guaranteed when resin is impregnated, in addition, the design freedom degree can be increased by the aid of a coil layering scheme during coil design, and the magnetic field uniformity index can be met more easily.
Drawings
Fig. 1 is a schematic view of a coil structure in the present invention.
Fig. 2 is a diagram of a coil structure designed by a conventional algorithm.
Fig. 3 is a mesh split diagram obtained by the algorithm of the present invention.
Fig. 4 is a current density distribution diagram obtained by linear programming.
Fig. 5 is a diagram of a coil structure designed by the algorithm of the present invention.
FIG. 6 is a contour plot showing the mean value of the peaks in the central region of 5ppm according to an exemplary embodiment of the present invention.
FIG. 7 is a contour plot of 5 Gauss magnetic field magnitude for an exemplary embodiment of the present invention.
Detailed Description
In a traditional superconducting magnet structure, the size of an end coil on a main framework is far larger than that of other coils, the end coil is farthest away from a cold head, and the heat radiation is the largest, so that the quenching times of the end coil are far larger than those of other coils. The invention provides a new coil structure aiming at the problem and a specific design method. This section describes the present invention in more detail with reference to specific embodiments. The main contents of the present invention are described below:
the embodiment of the invention discloses a novel superconducting magnet coil structure, wherein a superconducting magnet coil is formed by connecting a plurality of solenoid coils in series, the central axes of all the solenoids are overlapped, the solenoid coils with the layer number exceeding a set numerical value N are divided into a plurality of coils with overlapped axial positions in the radial direction and are separated by using partition plates, and N is a preset positive integer. The schematic diagram of the coil structure in the invention is shown in fig. 1.
For a coil with a larger number of layers, not only is the thermal stability worse, but it is also more difficult to impregnate the resin. In the invention, the isolation plate is added in the coil layer, so that the two problems can be solved simultaneously. If the resin is simply impregnated, an insulating plate can be used as a partition plate, and channels for facilitating the resin to flow are added on the insulating plate. If the problems of heat dissipation and resin impregnation are solved at the same time, a metal plate coated with an insulating layer on the surface may be used, and slits or holes may be added to the metal plate to facilitate the resin circulation, and the metal plate may be connected to a cold head to rapidly cool the superconducting wire around the separator. It is generally recommended to apply a separator for every 20-30 layers of wire.
The following describes a method of designing a coil using this structure. If the conventional method is adopted for design, and the coils with a large number of layers are artificially divided into a plurality of layers after the design is finished, the magnetic field of the coils in the central area can be greatly influenced. Therefore, new design methods must be studied.
The superconducting magnet coil with a novel structure is designed by adopting a hybrid algorithm. The design steps are divided into two steps, the first step is that the wiring area range of the main coil and the shielding coil and the magnetic field value uniformity in a magnetic field uniform area are set, the maximum number of layers allowed by each solenoid coil, the initial thickness of the isolation plate and the size of the superconducting wire are determined, the position where the isolation plate is placed in the wiring area is predetermined, the wiring area is divided into a plurality of layers along the radial direction according to the position of the isolation plate, then the wiring area is subjected to grid division, current clusters meeting the design requirements in the wiring area are determined by adopting an optimization algorithm, each current cluster is equivalent to one solenoid coil, the size, the position and the working current of each solenoid coil are determined according to the distribution of the current clusters, and the equivalent coils of the current clusters which are located on different layers and have the same axial position are made to be equal in length and the same in axial position; and secondly, further optimizing the parameters of each solenoid coil by adopting a nonlinear programming algorithm to obtain the coil parameters meeting the design requirements. The first step of the algorithm is suggested to be optimized by adopting a linear programming algorithm, the second step is a nonlinear optimization problem, and optimization algorithms such as a genetic algorithm, a simulated annealing algorithm, an interior point method and the like can be adopted, wherein the optimization is carried out by adopting the interior point method.
The first step of optimization comprises the following steps:
(1) Determining coil design parameters and the maximum layer number N of the coil, wherein the coil design parameters comprise the size of a wiring area and the intensity B of a background field 0 Imaging area range, magnetic field uniformity e, maximum operating current I max The height h and the width w of the superconducting wire and the initial thickness delta of the isolation plate are calculated;
(2) Taking any two-dimensional plane passing through the axis of the coil, establishing a coordinate system in the plane, setting the axis direction as Z-axis direction and the direction vertical to the Z-axis as R direction, and making the inner diameter of the wiring area of the main coil be R p,min (i.e., the minimum allowable inner diameter of the main coil), outer diameterIs R p,max (i.e., maximum allowed outside diameter of the primary coil) and left axial coordinate Z p,min (i.e., the minimum axial coordinate value allowed for the main coil), and the right axial coordinate is Z p,max (i.e., the maximum axial coordinate value allowed for the main coil), the main coil wiring region is radially positioned at [ R ] p,min +gNh+(g-1)Δ,R p,min +g(Nh+Δ)]The area of the wiring area is determined as the position of the g-th layer of the isolation board, wherein g is a positive integer, the wiring area is radially divided into a plurality of layers according to the position of the isolation board, then rectangular grid division is carried out on each layer of the wiring area, and the total grid number is represented by M;
(3) Solving the following optimization problem with constraint conditions:
s.t.
|J m |≤J MAX
in the above formula, V 1 Representing the homogeneous field region, V, within the coil 2 Denotes the stray field region outside the coil, K1 and K2 denote V respectively 1 、V 2 Number of samples in, J m Denotes the current density, p, within the grid numbered m m Denotes the radial coordinate of the center of the grid numbered m, B max Represents the maximum value of magnetic induction intensity allowed at the sampling point outside the coil, J MAX Represents the maximum current density allowed in the wiring area, alpha, beta and gamma are self-defined parameters,
at the sampling point when the unit current density is uniformly distributed, the grids numbered m respectively
The axial magnetic induction and the radial magnetic induction are generated.
(4) And (4) obtaining initial parameters of the coil according to the solution of the step (3).
In order to solve the above mathematical model by using a linear programming algorithm, the sign of the absolute value in the objective function needs to be removed. There are many ways to remove the absolute value. One method is to predetermine the direction of the current in the wiring area, e.g., forward current on the main bobbin and reverse current on the shield bobbin. The method in the patent "a superconducting magnet coil design method" (201910572326.4) may also be adopted.
The mathematical model for the second step of optimization is as follows:
s.t.
z 1,n+1 -z 2,n ≥δ,1≤n≤C-1,n≠C p
ρ 1,n ≥R p,min ,ρ 2,n ≤R p,max ,1≤n≤C p
ρ 1,n ≥R s,min ,ρ 2,n ≤R s,max ,C p +1≤n≤C
ρ 2,n -ρ 1,n ＝wT r,n ,1≤n≤C
z 2,n -z 1,n ＝hL z,n ,1≤n≤C
z 1,v+n ＝z 1,v ,1≤n≤Γ
Δ 1 ≤ρ 1,v+n -ρ 2,v+n-1 ≤Δ 2 ,1≤n≤Γ
I≤I max
in the above formula, the symbol z 1,n 、z 2,n Respectively representing the axial coordinates, p, of the left and right ends of the coil n 1,n 、ρ 2,n Respectively representing the radial coordinates of the inner and outer ends of the coil n, z 1,1 Is the axial coordinate of the left end coil of the main coil,
is the right axial coordinate of the coil at the right end of the main coil,
is the left axial coordinate, z, of the left coil of the shield coil 2,C Is the right-hand axial coordinate, T, of the right-hand coil of the shield coil r,n 、L z,n Respectively, the number of turns and the number of layers of the coil n, delta the axial minimum spacing of the two coils,
the sample points numbered i are indicated,
respectively representing sample points
And sampling point
The axial component of the magnetic field at (a),
showing the coil at
Amplitude of the magnetic field generated, C p Denotes the number of main coils, C denotes the total number of coils, R p,min 、R p,max Respectively representing the minimum and maximum allowable inner and outer diameters, Z, of the main coil p,min 、Z p,max Respectively representing the minimum and maximum axial coordinate values, R, allowed for the main coil s,min 、R s,max Respectively representing the minimum and maximum allowable inner and outer diameters, Z, of the shield coil s,min 、Z s,max The minimum and maximum coordinate values of the axial direction allowed by the shield coil are respectively shown, I is the working current, and the coil numbers which need to be separated by the isolation plate are v to v + gamma, delta 1 、Δ 2 The minimum thickness and the maximum thickness of the separator are indicated.
Through the two-step optimization, the final structure of the coil can be obtained.
In the first and second optimization algorithms, the magnetic field at the sampling point needs to be calculated, and a magnetic field calculation method is described below. In the first step, a wiring area is divided into a plurality of grids, current density in each grid is uniformly distributed, and each grid can be regarded as a current-carrying circular ring. In the second step of non-linear optimization, the solenoid coil is also composed of a plurality of current-carrying rings, and the magnetic field generated by the solenoid is equal to the superposition of the magnetic fields generated by all the current-carrying rings. The problem is thus solved by the calculation of the magnetic field of the current-carrying loop. The magnetic field of the current-carrying ring can be calculated by the Biao-Saval formula, which is referred to in many books relating to electromagnetic fields and will not be described in detail here.
The simulation results are given below according to specific examples. Designing a superconducting magnet coil with a symmetrical structure, wherein the design requirements are as follows: the background field is 1.5T; the peak-to-peak magnetic field uniformity in a spherical region having a diameter of 45cm was 10ppm; the stray magnetic field is required to be not more than 5 gauss in the region of R being more than or equal to 2.5m and Z being more than or equal to 4.0 m; the amplitude of the working current is I less than or equal to 460A; the wire size is: 1.5mm by 2.5mm. The area range of the main coil is as follows: r is more than or equal to 0.45m and less than or equal to 0.6m, and | Z | is more than or equal to 0 and less than or equal to 0.65m; the range of the area where the shielding coil is located is as follows: r is more than or equal to 0.8m and less than or equal to 0.8m; the absolute value of Z is more than or equal to 0.3m and less than or equal to 0.65m.
The magnet coil was first designed using conventional design schemes, with the resulting coil dimensions shown in table 1 and the coil configuration shown in fig. 2. Because the coils are of a symmetrical structure, only data of the Z-axis positive half shaft are given in the table, and the coil distribution of the Z-axis positive half shaft is also only shown in fig. 2.
TABLE 1 coil size using conventional algorithm
| Coil numbering | ρ 1 | ρ 2 | z 1 | z 2 |
| 1 | 0.4500005383 | 0.4740005383 | 0.0000000000 | 0.0325000000 |
| 2 | 0.4500000000 | 0.4740000000 | 0.0927549497 | 0.1677549497 |
| 3 | 0.4507155794 | 0.4777155794 | 0.2464160142 | 0.3514160142 |
| 4 | 0.4500000000 | 0.5400000000 | 0.5549989033 | 0.6499989033 |
| 5 | 0.7737147833 | 0.7977147833 | 0.4374999150 | 0.6499999150 |
In this design, the end turns have 60 layers, and it can be seen that the size of the end turns is very large, which makes it difficult to dissipate heat and impregnate resin. The coil structure of the present invention is adopted below to divide the end coils into two layers for redesign.
The spacer position is first determined. Assuming that a spacer is placed on each 28 layers of wires of the opposite end coil, the thickness of the spacer is 1mm, the height of the wires is 1.5mm, and the radial coordinates of the spacer are located [0.492mm,0.493mm ] according to calculation. The main coil wiring region is divided into two parts with this region as a boundary and mesh division is performed, as shown in fig. 3. Then, a linear programming algorithm is used for optimization, and the obtained current density distribution is shown in fig. 4. Each current cluster in fig. 4 is equivalent to one coil for a total of 6 coils. Then, the coil size was further optimized by the interior point method, and the resulting coil structure is shown in fig. 5, and the coil size is shown in table 2. The table also gives data only for the positive z-axis half.
Table 2 coil size obtained by the algorithm of the present invention
| Coil numbering | ρ 1 | ρ 2 | z 1 | z 2 |
| 1 | 0.4500001113 | 0.4740001113 | 0.0000000000 | 0.0325000000 |
| 2 | 0.4504883336 | 0.4744883336 | 0.0891082766 | 0.1641082766 |
| 3 | 0.4500000282 | 0.4770000282 | 0.2374890180 | 0.3424890180 |
| 4 | 0.4500000000 | 0.4920000000 | 0.5392339176 | 0.6417339176 |
| 5 | 0.4930000176 | 0.5350000176 | 0.5392339176 | 0.6417339176 |
| 6 | 0.7706924374 | 0.7916924374 | 0.4049996403 | 0.6499996403 |
The coil is verified to have 8ppm of magnetic field peak-to-peak uniformity in a sphere with the radius of 22.5cm, and meets the design requirement. The magnetic field position distribution with a deviation of 5ppm from the central magnetic field is shown in fig. 6, and the 5 gauss line position is shown in fig. 7. It can be seen from the figure that the magnetic field in the center of the coil and the stray magnetic field outside the coil both meet the design requirements. It should be noted that, in order to clearly show the position of the partition, the vertex of the mesh in fig. 2 and 3 is the center point of the actual mesh, and thus the radial distance in the figure appears to be larger than 1 mm.
The foregoing illustrates and describes the principles, general features, and advantages of the present invention. It should be understood by those skilled in the art that the above embodiments do not limit the present invention in any way, and all technical solutions obtained by using equivalent alternatives or equivalent variations fall within the scope of the present invention.
Claims (6)
1. A novel superconducting magnet coil design method is disclosed, wherein a superconducting magnet coil is formed by connecting a plurality of solenoid coils in series, the central axes of all solenoids are overlapped, the solenoid coils with the layer number exceeding a set numerical value N are divided into a plurality of coils with overlapped axial positions in the radial direction and are separated by using partition plates, wherein N is a preset positive integer; the method is characterized in that the design step is divided into two steps, the first step is that the wiring area range of a main coil and a shielding coil and the magnetic field uniformity in a magnetic field uniform area are set, the maximum number of layers allowed by each solenoid coil, the initial thickness of an isolation plate and the size of a superconducting wire are preset, the position where the isolation plate is placed in the wiring area is preset, the wiring area is divided into a plurality of layers along the radial direction according to the position of the isolation plate, then the wiring area is subjected to grid division, current clusters meeting the design requirement in the wiring area are determined by adopting an optimization algorithm, each current cluster is equivalent to one solenoid coil, the size, the position and the working current of each solenoid coil are determined according to the current cluster distribution, and the equivalent coils of the current clusters which are located on different layers and have the same axial position are equal in length and the same in axial position; secondly, further optimizing the parameters of each solenoid coil by adopting a nonlinear programming algorithm to obtain coil parameters meeting the design requirements; the first step adopts a linear programming algorithm for optimization, and the second step adopts an interior point method for optimization;
the first step of optimization comprises the following steps:
(1) Determining coil design parameters and the maximum number N of layers of the coil, wherein the coil design parameters comprise the size of a wiring area and the intensity B of a background field 0 Imaging area range, magnetic field uniformity e, maximum operating current I max The height h and the width w of the superconducting wire and the initial thickness delta of the isolation plate are calculated;
(2) Taking any two-dimensional plane passing through the axis of the coil, establishing a coordinate system in the plane, and setting the axis direction as Z-axis direction and the direction vertical to the Z-axis as R direction to make the inner diameter of the wiring region of the main coil be R p,min Outer diameter of R p,max Left axial coordinate of Z p,min Right axial coordinate of Z p,max The main coil wiring region is radially located at [ R ] p,min +gNh+(g-1)Δ,R p,min +g(Nh+Δ)]Is defined as the position of the g-th layer of the isolating plate, wherein g is a positive integer according toThe wiring area is radially divided into a plurality of layers by the position of the isolation board, then rectangular grid division is carried out on each layer of wiring area, and the total grid number is represented by M;
(3) Solving the following optimization problem with constraint conditions:
s.t.
|J m |≤J MAX
in the above formula, V 1 Representing the homogeneous field region, V, within the coil 2 Denotes the stray field region outside the coil, K1 and K2 respectively denote V 1 、V 2 Number of internal sampling points, J m Denotes the current density, p, within the grid numbered m m Radial coordinate of center of grid numbered m, B max Represents the maximum value of magnetic induction intensity allowed at the sampling point outside the coil, J MAX Represents the maximum current density allowed in the wiring area, alpha, beta and gamma are self-defined parameters,
grid numbered m respectively at the sampling point when uniformly distributing the unit current density
Parturient of obstetricsRaw axial magnetic induction and radial magnetic induction;
(4) Obtaining initial parameters of the coil according to the solution of the step (3);
the mathematical model for the second step of optimization is as follows:
s.t.
z 1,n+1 -z 2,n ≥δ,1≤n≤C-1,n≠C p
ρ 1,n ≥R p,min ,ρ 2,n ≤R p,max ,1≤n≤C p
ρ 1,n ≥R s,min ,ρ 2,n ≤R s,max ,C p +1≤n≤C
ρ 2,n -ρ 1,n ＝wT r,n ,1≤n≤C
z 2,n -z 1,n ＝hL z,n ,1≤n≤C
z 1,v+n ＝z 1,v ,1≤n≤Γ
Δ 1 ≤ρ 1,v+n -ρ 2,v+n-1 ≤Δ 2 ,1≤n≤Γ
I≤I max
in the above formula, the symbol z 1,n 、z 2,n Respectively representing the axial coordinates, p, of the left and right ends of the coil n 1,n 、ρ 2,n Respectively representing the radial coordinates of the inner and outer ends of the coil n, z 1,1 Is the axial coordinate of the left end coil of the main coil,
is the right axial coordinate of the coil at the right end of the main coil,
is the left axial coordinate, z, of the left coil of the shield coil 2,C Is the right-end axial coordinate of the right-end coil of the shielding coil, and K1 and K2 are respectively the uniform magnetic field area V in the coil 1 And the stray field region V outside the coil 2 Number of sampling points, T r,n 、L z,n Respectively, the number of turns and the number of layers of the coil n, delta the axial minimum interval of the two coils,
the sample points numbered i are indicated,
respectively representing sample points
And sampling point
The axial component of the magnetic field at (a),
showing the coil at
Magnitude of the magnetic field generated, B max Allowed at sampling point outside coilMaximum value of magnetic induction intensity, C p Indicates the number of main coils, C indicates the total number of coils, R p,min 、R p,max Respectively representing the minimum and maximum allowable inner and outer diameters, Z, of the main coil p,min 、Z p,max Respectively representing the minimum and maximum axial coordinate values, R, allowed for the main coil s,min 、R s,max Respectively representing the minimum and maximum allowable inner and outer diameters, Z, of the shield coil s,min 、Z s,max Respectively representing the minimum and maximum axial coordinate values allowed by the shielding coil, w and h respectively representing the width and height of the superconducting wire, I is the working current, I max The coils, which need to be separated by spacers for maximum allowable current, are numbered v to v + Γ, Δ 1 、Δ 2 The minimum thickness and the maximum thickness of the separator are indicated.
2. A novel superconducting magnet coil structure, characterized in that the superconducting magnet coil is obtained by the design method according to claim 1.
3. The novel superconducting magnet coil structure of claim 2, wherein N is in a range of 20-30.
4. A novel superconducting magnet coil structure according to claim 2, wherein the isolation plate is a metal plate coated with an insulating layer.
5. A novel superconducting magnet coil structure according to claim 2 wherein there are gaps or holes in the spacer that allow resin to flow through.
6. The novel superconducting magnet coil structure according to claim 4, wherein the separator plate is connected with a magnet cold head.
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104007406A (en) * | 2014-06-13 | 2014-08-27 | 河海大学 | Method for designing elliptic cylindrical surface transverse gradient coil based on spatial alternation |
| CN104198968A (en) * | 2014-08-11 | 2014-12-10 | 河海大学 | Horizontal gradient coil and manufacturing method thereof |
| CN111507039A (en) * | 2020-04-26 | 2020-08-07 | 河海大学 | Design method for copper sheet cutting type gradient coil |
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| JPH09129042A (en) * | 1995-11-01 | 1997-05-16 | Hitachi Ltd | Oxide superconductive coil, oxide superconductor, and its manufacture |
| JP4607540B2 (en) * | 2004-10-21 | 2011-01-05 | 三菱電機株式会社 | Superconducting coil and manufacturing method thereof |
| JP4757129B2 (en) * | 2006-07-20 | 2011-08-24 | 三菱電機株式会社 | Superconducting magnet |
| RU2505760C2 (en) * | 2008-09-09 | 2014-01-27 | Конинклейке Филипс Электроникс, Н.В. | Heat exchanger with horizontal finning for cryogenic cooling with repeated condensation |
| CN102176368B (en) * | 2011-01-24 | 2012-10-03 | 中国科学院高能物理研究所 | Optimization and design method for MRI (magnetic resonance imaging) superconducting magnet |
| CN103187139A (en) * | 2011-12-28 | 2013-07-03 | 上海联影医疗科技有限公司 | Magnetic resonance superconducting magnet integrated coil and production method thereof |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN104007406A (en) * | 2014-06-13 | 2014-08-27 | 河海大学 | Method for designing elliptic cylindrical surface transverse gradient coil based on spatial alternation |
| CN104198968A (en) * | 2014-08-11 | 2014-12-10 | 河海大学 | Horizontal gradient coil and manufacturing method thereof |
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