Structural optimisation tools for iron cored permanent magnet generators for large direct drive wind turbines

As wind turbines increase their power output, their size and mass grows as well. The development of offshore wind farms demands higher reliability in order to minimise the maintenance cost. Direct drive electrical generators can be such a reliable solution since they omit the gearbox from the drivetrain. Their large masses though make them difficult to transfer and assembly. This paper will investigate an analytical and a finite element analysis optimisation (FEA) technique developed for minimising the structural weight of a direct drive generator. The optimisation techniques are then applied on different generator types to provide valuable conclusions and comparisons.