THE OPTIMAL DESIGN OF PASSIVE SHIMMING ELEMENTS FOR HIGH HOMOGENEOUS PERMANENT MAGNETS UTILIZING ENSITIVITY ANALYSIS

摘要

This paper presents a useful and simple method to design the passive shimming system for homogeneous permanent magnets based on numerical optimization. To simulate the effects of manufacturing and assembling tolerances, the actual geometrical parameter of the magnet with a derivation is suggested. Then, the optimal design model of a passive shim system is set up to correct the derivative of field homogeneity. The numbers, sizes and locations of the passive shims are optimized by steepest descent algrithm combined with design sensitivity analysis. Two implementations show the proposed method can achieve required homogeneity of the field with the minimum quantity of ferromagnetics.