Multi-watt electric power from a microfabricated permanent-magnet generator

This paper presents the design, fabrication, and characterization of permanent magnet (PM) generators for use in microscale power generation systems. The generators are three phase, axial flux, synchronous machines, each consisting of a multipole surface wound stator and PM rotor. The microfabricated windings, with small interconductor gaps and variable width geometry, are the key enabler for high power density. At a rotational speed of 120,000 rpm, one such generator demonstrates 2.6 W of mechanical-to-electrical power conversion and, coupled to a transformer and rectifier, delivers 1.1 W of DC electrical power to a resistive load. This Watt-scale electrical power generation demonstrates the viability of scaled PM machines for practical applications.