Comparison Between Different Design Topologies for Multi-Megawatt Direct Drive Wind Generators Using Improved Second Generation High Temperature Superconductors

Various design topologies were investigated to study the weights and costs for a direct drive wind turbine generator using improved second generation (2G) YBCO high temperature superconductors (HTS). Five different design topologies using combinations of air core, iron core, salient and non-salient configurations for both stator and rotor were considered for a generator with the nominal rating of 10 MW, 8 RPM and 3300 V. The main objective of the investigation was to minimize the HTS quantities and the reduction of total cost to achieve the same rating performance. The electromagnetic design was performed using transient finite element modeling including the improved HTS conductor characteristic properties. The mechanical design includes the support structures for both full load operation and sudden three-phase terminal fault conditions which can cause severe stresses.