Lifetime Cost Assessment of Permanent Magnet Synchronous Generators for MW Level Wind Turbines

Wind turbines with higher power ratings are desired to reduce construction and maintenance time and increase energy yield. However, the high capital expenditure (CAPEX) at the start of the project presents a hurdle for such technology especially for gearless permanent magnet synchronous generators (PMSGs). This paper addresses research questions associated with the method by which the energy per cost is calculated. It aims at presenting a more accurate cost calculation based on a combination of methods that takes into account lifetime operation of wind turbines. The proposed method is used to evaluate typical PMSGs designed and reported in this paper as well as others available in the technical literature. The new method´s outcome is compared to conventional methods. It is shown that lifetime cost calculations came in favor of gearless PMSGs, which has high CAPEX. It is also shown that when lifetime cost is included in the design optimization, it produces machines that provide lifetime revenues significantly higher than the extra CAPEX required.