Analytical Method for Overhang Effect of Surface-Mounted Permanent-Magnet Motor Using Conformal Mapping

摘要

In this paper, an analytical method for predicting the rotor overhang (OH) effect is presented using two types of conformal mappings (CMs), which are the r-θ and zr plane CMs. First, the no-load air-gap flux density (AFD) of a slotted air gap without OH is determined using the rθ plane CM. Second, the complex relative air-gap permeance (CRAP) in the zr plane is obtained by the zr plane CM. This helps in taking the OH effect into account. Finally, the no-load AFD of the slotted and OH air gaps in cylindrical coordinates is derived from the no-load AFD in the rθ plane with CRAP along the z-axis. The accuracy of the presented method is verified by comparing the results of no-load analysis with those of 3-D finite-element analysis.