2D field calculation of pure permanent magnet by using current pair model

This paper presents a method to model the permanent block as the current pairs for calculating the magnetic fields. In 2D complex plane, by using current pairs to represent the permanent block, the field in the space can be given a complex shape. When one transfers it into Taylor series, easy axis condition and the field strength inside the magnet aperture or in outside space can be derived when one wants to get pure 2N-poles field in the concerned space. The image effect, which changes an outward permanent magnet into an inward one when an iron shield surrounds, is also discussed in this paper. Magnetic efficiencies between several types of permanent magnets are also presented in this paper.