849 results about "Superconducting Coils" patented technology

The invention discloses a superconducting magnet quench detection early warning system and method based on skeleton current, and relates to the field of superconducting magnet quench detection, and the method comprises the steps: constructing an electrothermal coupling finite element model of a superconducting magnet and a conductive skeleton; simulating different quench events based on the electrothermal coupling finite element model; according to different quench events, quench judgment threshold values and different levels of quench severity index grading threshold values are determined; when the superconducting magnet is out of service, acquiring a skeleton current signal that the current of the superconducting magnet is shunted to the conductive skeleton; based on the skeleton current signal, according to the quench judgment threshold value and the quench severity index grading threshold value, grading early warning and protection response are conducted on the superconducting magnet quench, nondestructive testing can be conducted on the superconducting magnet quench, grading evaluation and optimization protection of the quench severity degree are achieved, and the safety of the superconducting magnet quench is improved. And the cost of the quench monitoring system is reduced.

The invention provides a multi-objective optimization method for non-planar coils of a star simulator and a star simulator magnet. The optimization method comprises the following steps: obtaining initial structures of a plurality of non-planar superconducting coils according to magnetic field configuration data of target plasma; according to the target magnetic field parameter, the engineering constraint parameter and the material constraint parameter of the configuration data, an objective function is constructed, the engineering constraint parameter comprises the engineering limit geometric parameter of the non-planar superconducting coil, and the material constraint parameter comprises the limit current carrying of the non-planar superconducting coil material; carrying out minimization solution on the target function to obtain optimized coil data; and performing materialization processing on the plurality of non-planar superconducting coils according to the optimized coil data to obtain a plurality of optimized non-planar superconducting coil models. According to the optimization method, a magnetic field matching-engineering feasibility-material safety three-dimensional constraint system is constructed, and the problem that the engineering cannot be realized on the ground is avoided.

The invention belongs to the technical field of superconducting wires, and relates to a niobium-tin composite superconducting wire and a preparation method thereof. The invention provides a Nb3Sn composite superconducting wire. The Nb3Sn composite superconducting wire sequentially comprises an Nb3Sn superconducting wire core, a barrier layer, a stable layer, a transition layer, a substrate layer and a functional layer from inside to outside, the transition layer is formed by mixing copper and a dielectric polymer, and the copper content is continuously decreased in a gradient manner from inside to outside; the substrate layer is the dielectric polymer; the functional layer is a plurality of protruding metal microstructures. According to the invention, the functional layer with the broadband electromagnetic stealth function is integrated on the basis of the Nb3Sn superconducting wire rod, so that the radar cross section is obviously reduced while the Nb3Sn superconducting wire rod bears high-density superconducting current and generates a strong magnetic field, and the technical problem that a high-field superconducting magnet system is easy to detect in an electromagnetic environment is solved.

The invention provides an assembling device for a superconducting coil of a star simulator, which comprises a support frame and an overturning assembly, the support frame is used for supporting on a supporting surface, the overturning assembly is arranged on the support frame and comprises an overturning support and an overturning driving mechanism, the overturning support comprises a rotating frame and an annular coil mounting frame, the coil mounting frame is used for mounting the superconducting coil, and the overturning driving mechanism is used for driving the rotating frame to rotate. The coil mounting frame is arranged on the rotating frame, surrounds the peripheral side of the superconducting coil and is fixedly connected with the rotating frame; the rotating frame is rotationally connected to the supporting frame around the first axis so as to adjust the opening angle of the overturning support relative to the supporting frame. The overturning driving mechanism is in transmission connection with the rotating frame and used for driving the rotating frame to rotate relative to the supporting frame. The assembling device is low in requirement for the operation environment, can adjust the installation angle of the found coil, has good adaptability and flexibility, and can cope with the complex installation working condition of the special-shaped superconducting coil of the star imitator.

The invention discloses a superconducting magnet coil quenching detection method and a related device, and relates to the technical field of superconducting magnets, and the method comprises the steps: collecting the total voltage of two ends of a superconducting magnet coil and the current of any end of the superconducting magnet coil in real time in the operation process of a superconducting magnet; based on a relation curve that the inductance of the superconducting magnet coil changes along with the current, the resistive voltage in the superconducting magnet coil is determined through the total voltage at the two ends of the superconducting magnet coil and the current at any end of the superconducting magnet coil; when it is detected that the resistive voltage is increased to a voltage threshold value or the continuous increasing duration of the resistive voltage exceeds a duration threshold value, it is judged that the superconducting magnet coil is quenched; through the method, the problems that an existing superconducting magnet quenching detection method is complex and low in detection sensitivity are solved.

The utility model relates to the technical field of magnet power supplies, and discloses an external superconducting magnet power supply, which comprises a plurality of power supply modules connected in parallel, the input end of each power supply module is electrically connected with a power grid, the output end of each power supply module is electrically connected with an external superconducting magnet, and the plurality of power supply modules connected in parallel are used for jointly supplying power to the external superconducting magnet; wherein the power supply module comprises a switching power supply sub-module which is electrically connected with a power grid and is used for converting alternating current of a first voltage level input by the power grid into high-frequency alternating current of a third voltage level; and the linear adjusting tube is electrically connected with the switching power supply sub-module and the outer superconducting magnet, and is used for converting the direct current of the third voltage level into direct current of a fourth voltage level and inputting the direct current of the fourth voltage level into the outer superconducting magnet. According to the utility model, through the switching power supply sub-module and the linear adjusting tube, the power factor and the energy utilization rate can be improved, the harmonic wave is small, the power grid is not polluted, and the stability of the output voltage is ensured.

This invention provides a method for detecting quench in a superconducting coil using leakage current, comprising the following steps: Step 1: Determine a first detection connection point on the main superconducting tape adjacent to a first current connection point, wherein the first detection connection point and the first current connection point are equipotential points; Step 2: Determine a second detection connection point on the sampling superconducting tape, wherein the second detection connection point and the second current connection point are equipotential points; Step 3: Connect a leakage current sampling circuit to the first and second detection connection points. If the leakage current sampling circuit detects leakage current, it is determined that quench exists in the main superconducting tape. This invention uses a leakage current sampling circuit to solve the problem of difficulty in sampling the quench voltage of superconducting magnets.

The invention discloses a superconducting magnetic levitation U-shaped track beam and a preparation method thereof, and belongs to the technical field of bridge engineering.The superconducting magnetic levitation U-shaped track beam is used for running of a magnetic levitation train with superconducting coils arranged on the two sides of a train body, and the track beam comprises a plurality of track beam sections which are sequentially spliced in the longitudinal direction; each track beam section comprises a main beam body and two side plates arranged on the two transverse sides of the main beam body respectively, the two side plates and the main beam body are integrally formed to form a U-shaped beam body structure, a maglev train can run in the U-shaped beam body, mounting grooves are formed in the inner side wall faces of the two side plates and used for mounting ground coils, and the invention further provides a preparation method of the superconducting maglev U-shaped track beam. The superconducting magnetic levitation U-shaped track beam is formed by splicing the multiple track beam sections, the main beam body and the two side plates in the track beam sections are integrally formed, the number of joints of the track beam is greatly reduced, the smooth performance of the track beam is guaranteed, and the overall stability of a magnetic levitation track system is improved.

The present invention discloses a superconducting motor quench detection method and apparatus based on rotational symmetry of a motor, belonging to the technical field of superconducting motor quench detection. The method includes: acquiring terminal voltages of each group of superconducting magnets in a superconducting motor, where the superconducting motor is pre-divided into at least two unit motors by using the rotational symmetry of the motor, and superconducting magnets located at corresponding positions are selected from the at least two unit motors as a group of superconducting magnets; calculating an absolute value of a terminal voltage difference of each group of superconducting magnets; and judging whether the absolute value exceeds a preset threshold, and if the absolute value exceeds the preset threshold, determining that the superconducting magnets are in a quench state. According to the present invention, induced voltages coupled by the terminal voltages of superconducting magnets are eliminated.

The invention discloses an installation positioning device, a superconducting magnet system and a fusion reactor device, and belongs to the technical field of fusion reactor engineering. The mounting and positioning device comprises a back plate assembly and a clamping assembly, wherein the back plate assembly is used for connecting a coil main body of the superconducting magnet system; the clamping assembly comprises a first insulating part, two clamping parts and a plurality of adjusting parts, and the first insulating part forms a mounting cavity which is at least used for accommodating a coil joint of the superconducting magnet system; the first insulating part is arranged between the two clamping parts, and the clamping parts are connected with the back plate assembly; the multiple adjusting pieces are arranged outside the first insulating piece in a surrounding mode, and the adjusting pieces are connected with the two clamping pieces respectively and used for adjusting the clamping force between the two clamping pieces. The coil connector is positioned and fixed for multiple times through the back plate assembly and the clamping assembly, the mechanical stability and the electrical insulation performance of the coil connector are improved, and the disassembly, assembly and maintenance cost is reduced.

The invention discloses a stress distribution evaluation method and device of a superconducting magnet, electronic equipment and a storage medium, and belongs to the field of stress distribution calculation.The method comprises the steps that a finite element model of the superconducting magnet is obtained, winding simulation and cooling simulation are sequentially carried out, winding stress distribution and thermal stress distribution are obtained through calculation, and a finite element model of the superconducting magnet is obtained; superposing the two to construct a pre-stress field; performing electromagnetic field modeling on the model to obtain electromagnetic force distribution; further carrying out multi-field coupling stress analysis, and identifying a key stress plane with most concentrated stress; and finally, constructing a two-dimensional plane stress model based on the plane, and inputting winding and thermal stress as pre-stress and electromagnetic force as external load into the two-dimensional model so as to efficiently calculate final stress distribution of the superconducting magnet. Therefore, by implementing the method, the problems of unreliable stress calculation and low solving efficiency in the prior art can be solved.

The invention provides a hoisting tool for a superconducting coil of a star simulator and a hoisting device for the superconducting coil of the star simulator. The hoisting tool comprises a connecting seat, a hoisting bracket, a first driving assembly and a second driving assembly, the whole hoisting support is of an arc-shaped rod structure and can be rotationally arranged on the connecting base in the first direction, the two ends of the hoisting support are located below the connecting base, and the star simulator superconducting coil can be rotationally clamped between the two ends of the hoisting support in the second direction; the first driving assembly is in transmission connection with the hoisting support and drives the hoisting support to rotate in the first direction. The second driving assembly is in transmission connection with the corresponding end of the star simulator superconducting coil and drives the star simulator superconducting coil to rotate around a second direction perpendicular to the first direction relative to the hoisting support. Through the combination of the first driving assembly and the second driving assembly, the star simulator superconducting coil can be driven to rotate in the two horizontal directions perpendicular to each other, and multi-angle adjustment of the mounting position of the star simulator superconducting coil is achieved.

The invention relates to the technical field of superconducting magnet manufacturing and insulation impregnation process optimization, and discloses a vacuum pressure impregnation process optimization method, device, equipment, medium and product, and the method comprises the steps: inputting a target porosity and a target permeability into an insulation layer homogenization fluid domain model to obtain a macroscopic homogeneous model; according to the macroscopic homogeneous model, a first corresponding relation between multiple technological parameters and the impregnation performance parameters under the boundary condition is determined through simulation, and the multiple technological parameters comprise at least two of the temperature, the glue injection parameter, the vacuum pressure, the resin viscosity and the resin curing kinetic parameter; and according to the plurality of first corresponding relations, optimizing the plurality of process parameters by taking the shortest filling time, the highest uniformity and the lowest residual bubble rate as optimization objectives to obtain an optimal process parameter combination of the vacuum pressure impregnation process. According to the method, the multiple process parameters are optimized, the multi-parameter optimization database can be established, and the optimal process combination scheme is obtained.

The purpose of the present invention is to provide a magnetic resonance imaging apparatus and a method for controlling a refrigerator. The magnetic resonance imaging apparatus increases the operating rate of an MRI apparatus by prolonging the replacement life of the refrigerator and reducing the replacement frequency of the refrigerator. And executing a cold head life prolonging mode. In the cold head life extension mode, regardless of the temperature of the superconducting coil, the displacer of the refrigerator is moved at a constant frequency lower than a predetermined upper limit frequency, and the drive frequency of the compressor drive unit adjusted by the compressor inverter is controlled in accordance with the temperature of the superconducting coil.

The invention discloses a rapid three-dimensional electromagnetic simulation method and verification device for a large-scale uninsulated coil, and aims to solve the problems of large calculation load, difficulty in homogenization, poor field-circuit coupling convergence and low result precision of the three-dimensional simulation of the existing large-scale uninsulated coil. The simulation method comprises the following steps: establishing a homogenized coil which does not divide specific turns, and setting anisotropic resistivity; constructing a current source area intercepted on the coil body and a free turn-to-turn resistance area connected in parallel with the current source area; applying current source excitation according to an open loop / closed loop coil; and the precision is ensured through radial grid encryption and result convergence verification. The verification device comprises a three-dimensional multi-turn verification coil, a direct current source, a multi-direction alternating external field applying module and a voltage and magnetic field measuring unit, direct current is supplied, an alternating external field is applied, and the simulation accuracy is measured and verified in real time. The method is simplified in modeling, rapid in calculation, good in convergence and high in precision, adapts to open-loop / closed-loop and single-cake / multi-cake coils, and is suitable for large uninsulated superconducting coils in rotary and linear motors, nuclear fusion equipment and the like.

An on-line program control excitation power supply with quench protection for a high-temperature superconducting magnet comprises a single-chip microcomputer for receiving control data, outputting control voltage through digital-to-analog conversion (DAC) of the single-chip microcomputer, and magnetizing a magnet coil through current stepping; a sampling signal is output to the liquid crystal screen to display corresponding voltage and current values in real time after being processed by the single-chip microcomputer analog-to-digital conversion ADC; voltage signals at the two ends of the magnet coil are sampled and returned to the single-chip microcomputer to be processed, when high voltage occurs, it is judged that the voltage signals are abnormal voltage signals, quench protection is carried out, the single-chip microcomputer outputs control signals to cut off connection between the magnet coil and the excitation power source, and residual energy of the magnet coil is released through the high-power thyristor. The provided excitation power supply has the characteristics of high power, high stability, good repeatability and good linearity; performing numerical control stepping output, gradually applying current to the superconducting coil, and slowly establishing a magnetic field; effective quench protection is achieved, and it is guaranteed that a magnet coil is not damaged by quench.

The application discloses a superconducting magnet coil box structure, comprising a coil body and a coil box, the coil body is in a ring structure, the inside of the coil box is formed with a ring-shaped inner cavity which is matched with the shape of the coil body, and the coil body is arranged in the ring-shaped inner cavity; an adjustable connecting component is connected between the outer ring wall and the corresponding inner wall surface of the ring-shaped inner cavity, and the adjustable connecting component is configured to allow the outer ring wall and the corresponding inner wall surface of the ring-shaped inner cavity to relatively move within a first threshold range in the radial direction of the coil body. When assembling, the radial gap between the box body and the coil does not need to be accurately controlled, and only the initial pre-tightening force of the adjustable connecting component needs to meet the design requirement. In this way, the stability of the superconducting magnet during use can be improved on the basis of ensuring that the coil box provides sufficient strength support for the coil body, and the disassembly and assembly steps of the coil assembly can be simplified, and the maintenance cost is reduced.

The invention discloses a temperature-variable superconducting magnet low-temperature testing system and method, and relates to the technical field of superconducting magnet low-temperature testing. The system specifically comprises a superconducting magnet circulation loop which is configured to be communicated with a superconducting magnet to be tested to form a closed circulation channel for helium flow; the heat exchanger is arranged in the superconducting magnet circulation loop and is configured to cool helium in the superconducting magnet circulation loop through heat exchange with an external low-temperature medium; the helium circulating pump is arranged in the superconducting magnet circulating loop and is used for driving helium to perform forced flow circulation in the closed-loop circulating channel; the temperature control assembly comprises a heater arranged in the superconducting magnet circulation loop; wherein the flow and the temperature of helium entering the superconducting magnet to be tested are controlled by adjusting the helium circulating pump and the heater. The invention aims to design a test system which does not need an expensive refrigerator, is simple and convenient to operate and can realize accurate control of a wide temperature zone and a forced flow cooling environment.

A cold storage material according to an embodiment contains a rare earth aluminum oxide containing at least one rare earth element selected from the group consisting of Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu, in which a Group 1 element is contained in an amount of 0.001 atom % or more and 10 atom % or less, and a maximum volumetric specific heat value in a temperature range of 2 K or more and 10 K or less is 0.5 J / (cm3·K) or more.

A superconducting magnet device (100) comprises: a superconducting coil device (110) provided with a superconducting coil (112) and a current introduction line (114) connected to the superconducting coil (112); a cryogenic device (120) that is provided with at least one cryogenic refrigerator (10) and that cools the superconducting coil device (110); at least one temperature sensor (130) provided to the superconducting coil device (110) or the cryogenic device (120); and a controller (140) configured to set a temperature target value on the basis of a state parameter pertaining to the superconducting magnet device (100), determine an operating parameter of the cryogenic refrigerator (10) on the basis of a comparison between a measured temperature from the temperature sensor (130) and the temperature target value, and operate the cryogenic refrigerator (10) using the determined operating parameter.

The invention belongs to the technical field of stainless steel, and discloses 4.2 K yield strength 1350 MPa grade steel for a fusion reactor superconducting magnet structure and a manufacturing method of the 4.2 K yield strength 1350 MPa grade steel for the fusion reactor superconducting magnet structure, and the steel comprises the following chemical components: 0.04-0.06% of C, 0.5-1.0% of Si, 6.5-8.0% of Mn, 19.5-21.0% of Cr, 10.0-12.0% of Ni, 1.5-2.0% of Mo, 0.25-0.30% of N and 0.15-0.25% of V. The deformation temperature interval of the high deformation rate and the low deformation rate during ply rolling is controlled by adopting continuous casting blank ply rolling, high-temperature-stage high deformation rate, low-temperature-stage low deformation rate and low-temperature solid solution; the steel plate has the advantages that the rolling temperature is lower than or equal to 1050 DEG C, the finish rolling temperature is higher than 800 DEG C, the thickness of the steel plate reaches 80 mm, the 4.2 K yield strength is 1350-1450 MPa, the tensile strength is 1750-1850 MPa, the ductility is 30%-40%, the fracture toughness is 155-170 MP.m < 1 / 2 >, and the room-temperature magnetic conductivity is smaller than 1.02. The problem of edge crack of the high-nitrogen austenitic stainless steel plate is solved.

The invention provides an iron yoke structure design method based on a variable density method, and is applied to the field of superconducting electrical iron yoke design. The method comprises the following steps: establishing a target equipment two-dimensional model comprising a superconducting coil, a workpiece and an iron yoke, and setting coil excitation, material attributes and electromagnetic boundary conditions; defining an iron yoke design space and dividing finite elements, and taking the relative density of the finite elements as a design variable; establishing a topological optimization model by taking the magnetic pole gap magnetic flux density as a target function and the yoke volume as a constraint; carrying out magnetic field finite element analysis by utilizing a material attribute interpolation model to obtain magnetic field distribution, and then calculating a magnetic pole gap magnetic flux density module value integral to obtain a target function value; solving the sensitivity of the target and the constraint function to the design variable, modifying the sensitivity, inputting a gradient optimization algorithm, and updating the design variable under the condition that the constraint is satisfied; and if the target function change is smaller than the convergence tolerance, outputting the yoke structure. The invention further provides an iron yoke structure, a device, equipment, a medium and a program product.

The invention relates to the technical field of superconducting magnet manufacturing and insulation impregnation process optimization, and discloses a VPI simulation time step length adjusting method, device, equipment and medium, the method comprises the following steps: obtaining a VPI simulation model and a target library Lambda number, and the VPI simulation model is provided with rheological characteristics and boundary conditions of resin; when the boundary condition is a single glue injection port based on a constant pressure boundary, determining a first maximum flow rate and a first minimum grid size of resin under the current time step length according to a VPI simulation model; and determining the next time step length according to the first maximum flow velocity, the first minimum grid size and the target library lambdan number. According to the method, the time step length is dynamically adjusted through the actual flow speeds of the resin in different stages, redundant calculation is avoided, and therefore the total simulation time is remarkably shortened.

Techniques are described for lowering strains applied to superconducting material in a superconducting magnet by arranging structural partitions between turns of the superconducting material that intercept and transfer strain to a mechanically stronger structure, such as the housing of the magnet. A structural partition may be formed with a feedthrough slit so that the superconducting material can easily pass through the partition. A number of structural partitions may be interspersed between groups of turns of superconducting material in a magnet so that forces can be sufficiently distributed by the partitions throughout the magnet. At the same time, the number of structural partitions may be selected to minimize the amount of space within the magnet occupied by the partitions that could otherwise be occupied by current-carrying superconducting material.

The present invention provides: a MgB2 superconducting wire that has a barrier layer of highly uniform thickness covering a MgB2 core and that reduces MgB2 filament defects and is suitable for thinning and lengthening; a MgB2 superconducting wire manufacturing method for manufacturing the same; a superconducting coil using the same; and a magnetic generator including the superconducting coil. A MgB2 superconducting wire (200) comprises: a core material (210); a MgB2 filament (220) in which a MgB2 core (221) is covered with a barrier layer (222); and a metal sheath (230). The MgB2 filament (220) has a barrier layer (222) thickness on the outer peripheral side of the wire not more than three times the barrier layer (222) thickness on the core side of the wire. The method for manufacturing the MgB2 superconducting wire includes a step for forming a single core wire, a step for forming an embedded material, a surface reduction processing step, and a heat treatment step. The embedded material is formed by arranging the single core wire in a recess formed in the outer surface of the core material or by incorporating a spacer in a gap.

The application relates to a hybrid energy storage capacity multi-objective optimization configuration method for power fluctuation suppression, determines grid-connected unbalanced power, establishes an OVMD mathematical model, determines an optimal modal decomposition layer number K, decomposes the grid-connected unbalanced power signal, and determines high and low frequency reconstruction component orders and a demarcation point of connotation modal components in combination with superconducting magnet charging and discharging cycle time, determines low frequency power components and high frequency components, takes the minimum full life cycle cost of the hybrid energy storage system and the minimum operation penalty cost as targets, establishes a superconducting-electrochemical hybrid energy storage capacity multi-objective configuration model, obtains a Pareto front solution set of optimization target parameters, and obtains a superconducting-electrochemical hybrid energy storage optimal configuration scheme. The beneficial effects are that the influence of subjective K value setting on the decomposition layer number is reduced, the applicability of VMD is improved, the global search capability is enhanced, the population diversity is increased, the algorithm convergence is improved, and the uniformity of the optimal solution distribution of the Pareto front is improved.

The invention discloses a reusable superconducting coil vacuum pressure impregnation tool and method, and relates to the technical field of superconducting coil preparation tools. Comprising a dipping tool cylinder, an upper cover plate, a lower cover plate, a coil outer support, a superconducting coil and a coil inner support, the two ends of the dipping tool barrel are detachably connected with the upper cover plate and the lower cover plate respectively; a vacuum joint is arranged on the upper cover plate; a glue injection opening is formed in the side wall of the dipping tool barrel; the coil outer support is arranged on the inner side of the superconducting coil, the coil inner support is arranged on the outer side of the superconducting coil, the coil outer support, the superconducting coil and the coil inner support are arranged on the lower cover plate, and the space between the coil outer support and the inner wall of the dipping tool barrel is filled with epoxy blocks. The device can adapt to superconducting coils of different sizes only by increasing or decreasing the volume of the filling epoxy block, the dipping tool does not need to be destructively disassembled when the coils are taken out, and it is ensured that the temperature is uniform when the whole tool is heated and cured through heating oil in an interlayer of the dipping tool.

An apparatus includes a magnet comprising an electrically superconductive coil adapted to function in a driven mode. A magnet controller (210) is connected to the magnet. A power supply (122) adapted to provide direct current (DC) power to the magnet. An electrical connection is provided between the magnet to provide the DC power to the magnet. A communication interface (206) adapted to communicate signals across the cable between the power supply (122) and the magnet controller (210). The signals between the communication interface (206) and the magnet controller (210) are high-frequency (HF) signals that do not substantially interfere with the DC power transmitted across the cable.

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.

The invention discloses a preparation method of Bi-2212 precursor powder capable of remarkably improving the phase density of Bi-2201 nanometer stripes in a Bi-2212 wire rod, and the Bi-2212 precursor powder capable of remarkably improving the phase density of the Bi-2201 nanometer stripes in the Bi-2212 wire rod is obtained by controlling the components of a precursor solution, adjusting in cooperation with a fine heat treatment method and controlling the molar ratio of Sr to Ca. According to the method disclosed by the invention, the components of the precursor solution are controlled, the large-size Bi-2201 phase is eliminated in combination with heat treatment, and the molar ratio of powder Sr to Ca is controlled to be within a proper range, so that the density of the nano stripe Bi-2201 phase in the Bi-2212 wire rod is improved, and the pinning performance of the Bi-2212 wire rod is favorably improved; the method is easy to operate, low in cost and high in controllability and operability, the cost performance of the Bi-2212 superconducting wire is improved, and rapid application of the Bi-2212 superconducting wire in the field of high-temperature superconducting magnets is further promoted.