Research Of The Three-Dimensional Magnetic Field Distribution Around A Rectangular Permanent Magnet

With increasing application of magnets in the magnetic levitation, the comprehensive understanding of the three-dimensional magnetic field becomes more important. Surrounding the special magnetic field distribution of the rectangular magnet, series research of fundamental experiments, theoretical analysis and computing simulations were presented.For the magnetostatic solution of a rectangular magnets'magnetic field, the accurate analytical calculation was chosen. Based on Ampere's molecular current hypothesis, the analytical model for rectangular magnet with only one magnetization direction was established. And the integral equation formulation for magnetic field of a rectangular magnet was obtained. It was indicated that the thickness of the magnet play more important role in effecting the magnetic field than the length and the width, and the strong magnetic filed in the magnetization direction was thin 53 times the width and 21times the thickness. According to the analytical solution for single magnet, the formulation for repulsive and attractive magnets was acquired. The effects of different magnet arrangements were described. The field analysis results were confirmed with the experimental results and other theoretical expressions including dipole magnet theory and scalar potential model.The three-dimensional magnetic field distribution for both single magnet and repulsive and attractive magnets was obtained from fundamental experiments performed mainly for single magnet and double magnets. It was shown that the magnetic field distribution longitudinal the magnetization direction was centrosymmetric and the one perpendicular the magnetization direction was anti- centrosymmetric. The characteristic of magnetic field distribution graph and the interaction between two magnets were described. The distribution shape of Hz, namely the magnetic field distribution longitudinal the magnetization direction, for different distances was presented.The three-dimensional simulations for many magnets'magnetic field based on the equation formulation of single magnet were performed. Two arranging manners were considered and the effect of gap between magnets was analyzed. The results showed that the wide constant magnetic field can be acquired by using many rectangular magnets, but the gap resulted in fluctuation that would cause negative effect to the control of magnetic field.