A Radially Outward Extended Permanent Magnet Overhang Technique for Electromagnetic Performance Enhancement in Permanent Magnet Machines

Abstract

This article proposes a structural approach to leverage the unused space created by the stator's end winding, with the goal of enhancing the machine's torque. To accomplish this, Permanent Magnets (PMs) are extended beyond the active stack, forming an overhang structure that boosts stator flux linkage and enhances torque delivery. This enables the design of a smaller motor that delivers the same torque output, offering a higher torque/power density. The proposed structure is also optimized and compared with alternative designs under the constraint of equal magnet volume to highlight its effectiveness. Furthermore, a Magnetic Equivalent Circuit (MEC) model of the proposed structure is developed and validated using Finite Element (FE) analysis. Experimental validation is also conducted, and the results are compared with the conventional overhang configuration.