Abstract

This paper presents a study on the demagnetization of a coreless axial flux permanent magnet synchronous generator (CAFPMSG) for a small hybrid vertical-axis wind turbine (VAWT). Two harsh operating scenarios that could compromise the functionality of the generator are analyzed: an overload caused by high wind speeds, and a short-circuit fault in the generator connection line. The study involves a comprehensive system characterization including the hybrid VAWT, load controller, and generator, followed by numerical simulations to analyze the behavior of the PMs under the harsh operating scenarios. The results indicate that even under rated operating conditions, partial demagnetization of the permanent magnets (PMs) may occur. Under overload conditions, the demagnetization effects become more pronounced, resulting in a torque reduction of approximately 15% compared to the ideal condition. Furthermore, short-circuit analysis reveals that around 13% of the PM material becomes fully demagnetized, compromising the integrity of the machine. © 2025 IEEE.