Design Improvement of a Spoke-Type PMSG with Ferrite Magnets to Reduce Space Harmonics

Abstract

In this study, the harmonics of the pole arc geometry on the air gap flux density between the magnets in the wind turbine generator with spoke-type magnet mounting were examined. In the study, two designs, design A and design B, were compared. While the air gap had a constant value along the pole arc in design A, the air gap increasing from the center of the pole to the edges was taken into account in design B. The geometry, material, and mounting position of the magnet used in permanent magnet machines affect the machine's performance. Currently, magnets consisting of iron, nickel, ferrite, samarium cobalt, and neodymium-iron-boron alloy are available. Limited supply and price instability of rare earth elements require alternative product designs. In the study, two designs with different rotor structures without changing the stator structure and properties were made, and their performance was examined. Space harmonics were determined by extracting the air gap flux waveforms of the designs. In accordance with the results obtained, much lower space harmonics were obtained with design B.