Design of Notched T-type IPMSG for Wind Turbine

Abstract

Permanent Magnet Synchronous Generator(PMSG) has advantages in high efficiency, long term reliability, and simple structure. For these reasons, PMSG has been actively studied and developed for wind turbine generator where high efficiency and reliability is very important issue. PMSG can be broadly divided into Surface Permanent Magnet Synchronous Generator(SPMSG) and Interior Permanent Magnet Synchronous Generator(IPMSG). In IPMSG, the rotor structure is more robust because magnets are burred in the rotor. Therefore, IPMSG is more suitable for high-speed machines where big centrifugal forces are applied on the rotor structure. In addition, the demagnetization of magnets can be reduced because magnets are isolated from the stator by the rotor core. In this thesis, the existing SPOKE-type IPMSG is redesigned to T-type IPMSG to optimize the generator dimension and to improve the power factor. To reduce the cogging torque, notches are designed and implemented on the surface of the rotor instead of expensive and cumbersome rotor skewing. Notching rotor has advantage in simple rotor structure and easy manufacturing compared to the skewing rotor. 2D Finite Element Method(FEM) is used to the electromagnetic analysis, thermal analysis and stress analysis. With these design modifications, the generator length could be reduced by 6% while keeping the same cogging torque level. This modification can contribute to reduce the manufacturing cost of the rotor significantly in material, and labor.