6-rpm 5MW axial flux multi-stage air cored permanent magnet generator design for vertical axis offshore wind turbines

Abstract

Although the onshore and offshore wind energy market is dominated by horizontal axis wind turbines, there is an increasing interest in the use offshore vertical axis wind turbines due to their potential advantages. At the same time, the gearbox problems encountered in wind turbines have increased the interest held towards direct-drive generator systems. The high torque requirements of direct-drive systems have increased both generator dimensions and mass. Permanent magnet C-GEN generators can be a good candidate for vertical axis wind turbines due to their lightweight structure, easy production and simple installation. In this study, a 6-rpm 5MW multi-stage air-cored generator model has been developed for direct-drive vertical axis wind turbines and an automatic a 2D finite element analysis software algorithm has been improved for generator design and optimization.