High-speed characterization and mechanical modeling of microscale, axial-flux, permanent-magnet generators

This paper reports the high-speed experimental characterization of a microscale, axial-flux, permanent-magnet (PM) generator to failure. A single-phase, open-circuit voltage of 0.9 V_rms was measured at 225 krpm, which corresponds to 3.3 W of DC power if the machine were connected via power electronics to a matched resistive load. Finite-element analysis was used to model and examine the mechanical design of the high-speed rotor assembly to increase the speed and, hence, output power of the device. Ultimately, rotor speeds of 325 krpm were achieved using a titanium rotor housing.