Low harmonic design and magnetic equivalent circuit modeling of fractional-slot concentrated-windings permanent-magnet machines

摘要

Due to their advantages of high efficiency, high power density, and strong fault-tolerance ability, fractional-slot concentrated-winding permanent-magnet (FSCW-PM) machines are of particular interest in the applications such as wind power generation and electric vehicles. However, FSCW-PM machines suffer from rich winding magnetomotive force (MMF) space harmonics by the armature reaction field, which may increase eddy current loss. In this paper, a new low harmonic FSCWP-M machine is designed, which can reduce some space harmonics of low order in the air-gap flux density. A new magnetic equivalent circuit (MEC) model is developed to analyze the designed PM machine, which offers less computation time and more calculation accuracy. Finally, a prototype machine is built and the measured results verify the theoretical analysis and the developed MEC model.