Design optimization of an 8 W, microscale, axial-flux, permanent-magnet generator

This paper presents the design optimization and characterization of a microscale, permanent-magnet (PM) generator, capable of supplying 8 W of dc power to a resistive load at a rotational speed of 305 000 rpm. The generator is a three-phase, axial-flux, PM machine, consisting of a stator with Cu surface windings and a multi-pole SmCo PM rotor. Optimization of the machine geometries has enabled a 30% improvement in power density (for the same rotational speed) over a previously reported machine. Furthermore, these design improvements, in combination with higher rotational speeds, have enabled a >7x improvement in total output power and a net power density of 59 W cm -3 .