Experimental Evaluation of a Rare Earth-Free Permanent Magnet Generator

Low speed, high torque machines are used in wind turbines where the turbine rotor is directly connected to generator. A permanent magnet synchronous generator using high-energy rare-earth magnets (PMs) one common choice for this application, but PMs have supply insecurities and cost risks. free 32-pole PM generator, ferrite a spoke-type rotor, use 12 kW experimental built tested. Voltages currents at load no measured, as well magnetic field end regions of machine. The can deliver required power nominal speed has low harmonic content output. electrical measurements compared two-dimensional finite element design calculations results lower than expected from simulations. measured voltage expected, requiring higher current calculated rated power. Three-dimensional simulations show that there leakage flux paths end-regions overlook, explaining discrepancy between measurements.