Finite Element Modeling And Parameter Optimization Of Halbach Permanent Magnet Array Field For Planar Motor

This article mainly studies the finite element modeling of the Halbach permanent magnet array magnetic field used in the planar motor and the optimization of structural parameters based on the finite element model.The planar motor has many advantages in its two-dimensional workbench application field,and its unique structural features make the planar motor more widely applicable.In the two-dimensional workbench,the planar motor is small in size,simple in structure,and large in working stroke.Compared with the double-deck lead screw guide rail pair structure,the two-dimensional worktable with another structure greatly reduces its own inertia and height,and has no mechanical wear,which simplifies the worktable structure.In practical applications,according to the large acceleration,speed and stability,a high-efficiency two-dimensional workbench with good dynamic characteristics is designed.Halbach permanent magnet arrays have been used in many fields such as medicine,high-speed motors,linear motors,high-precision servo motors,high-energy physics,multi-degree-of-freedom motors,and magnetic levitation train systems.Halbach array permanent magnets have special magnetic field characteristics.In actual production,they have broad prospects in permanent magnet motors,nuclear magnetic resonance,magnetic refrigeration and other corresponding fields.In this paper,the optimization objective is to maximize the value of the fundamental wave components in X,Y and Z directions of the magnetic flux density distribution of the permanent magnet array.In finite element modeling,how to optimize the parameter setting is very important.The ratio between the thickness of the permanent magnet and the width of the permanent magnet was taken as the optimization parameter,and the symbols t₁and k(w₂/w₁)were used to express the parameters.The optimal ratio of the width of the permanent magnet and the thickness of the permanent magnet array are obtained by comparing one by one.The optimization method is to select one or two optimization methods according to the actual situation.The main optimization methods are COBYLA and BOBYQA,which respectively represent linear approximation constrained optimization and quadratic approximation bounded optimization,both of which are the optimization of the objective function.Whether the width of the permanent magnet array is optimized or the thickness of the permanent magnet array is optimized,a conclusion can be drawn:when k is0.666666 or about 0.67,the magnetic flux density through the permanent magnet array is the maximum value,and the thickness of the permanent magnet array is a constant value.When k is a constant value,the thickness of the permanent magnet array gradually increases,and within a certain range,the value of the magnetic flux density changes in a curve.When it exceeds this range,the value of the magnetic flux density gradually approaches a constant value.