Design of a highly efficient 1kW concentric wound IPM machine with a very wide constant power speed range

This paper presents a design process of a 1kW interior permanent magnet machine with concentrated non-overlapping windings. The main focus of this design is to achieve a very wide constant power speed range and optimal efficiency throughout the entire speed range. The authors will explain how the increase in airgap harmonic components caused by concentrated windings affects core and magnet losses; how the speed range is optimized and how losses are minimized by machine geometrical variations, construction strategies and appropriate selection of materials. Finite element analysis with transient and steady-state AC magnets in FLUX2D is used for predicting machine loss and field weakening performance due to its ability to handle complex calculations with non-linear material properties and precise geometry variations.