High-Voltage Direct-Driven Wind Turbine Generating System

Research Project, 2020 –

This activity has the long-term aim to achieve a generating system for very large wind turbines, in particular sea-based ones, outputting a high voltage. The focus is to output DC, but AC-connection is also possible. The targets are high efficiency, low environmental and ethical impact as well as robustness. Also weight is an important target, where the elimination of a transformer is a very positive aspects, however, direct-driven designs seems to inevitable have
a higher weight compared to geared-solutions. In the long term, in-slot cooling is thought to be used, which might give a possibility of reaching a weight comparable to a geared-solution, however, this remains to be proved at a later stage. Furthermore, a single gear-step is also to be considered at a later stage. The objective of this project is to design a 20 MW wind generating system, feeding out power into a 40-70 kV DC system. The system shall be directly driven, i.e. gearless. A permanent magnet design is to be compared with a design using electrical magnetization. The suitable number of poles is to be established in relation to size and efficiency.