Spoke type Permanent Magnet Synchronous Generator Design considering Magnetizing and Cogging Torque

Abstract

Nowadays, in wind power generator systems, the use of a permanent magnet synchronous generator with high output density per unit volume is increasing. Among them, the magnetization performance of the spoke-type permanent magnet synchronous generator (PMSG) is low compared to that of the other types of permanent magnet synchronous generators owing to its structural characteristics. Magnetization performance is critical because it is directly related to demagnetization and mass productivity of permanent magnets, and it can cause a reduction in the load performance when non-magnetization occurs owing to low magnetization performance. In addition, an important parameter in the wind turbine is the starting performance, which is affected by the cogging torque of the permanent magnet synchronous generator. Therefore, in this study, we propose a spoke-type PMSG rotor shape design that considers magnetization and cogging torque. The magnetization principle and factors affecting the magnetization performance were analyzed, and a rotor shape with improved magnetization performance was designed. In addition, the rotor barrier asymmetric structure for reducing cogging torque was applied and the performance of the final model was analyzed through finite element analysis (FEA). The feasibility was verified through production and testing of prototypes.