2-D Analytical Modeling of Surface Mounted Permanent Magnet Machines With External Rotor Core

Abstract

This paper presents a computationally efficient two—dimensional (2-D) analytical framework for predicting the electromagnetic response of Permanent Magnet (PM) machines with external rotor core. The machine structure is divided into multiple subdomains and Maxwell equations are solved by applying relevant boundary conditions. The stator slots are modeled via virtual surface magnetization currents on the outer surface of the stator bore. To improve the precision of the model, the magnetization current is injected on both the teeth lateral sides and the slot opening area. As a result, the presented model provides more accurate results with respect to the standard virtual current model. The presented model is applied on a fractional slot concentrated winding (FSCW) PM machine with external rotor core, and the no-load electromagnetic performance metrics are calculated. For validation purposes, analytical results are supported via finite element method (FEM) and experimental tests.