Performance Analysis of HTS Excited 5 MW Medium-Speed Wind Turbine Generators With Different Stator Feeding Concepts

High-temperature superconducting (HTS) field windings in synchronous generators are a promising alternative to a rare-earth permanent magnet excitation. Medium-speed wind generators can profit from superconducting field windings with low material requirements by simultaneously avoiding the failure-prone high-speed gear stage. Such a 5 MW generator system is simulated in the entire operating speed range at full and partial load. Besides the usual full-size inverter, a cheap diode bridge connection to the grid is possible with HTS excitation. The additional generator losses due to the diode rectifier are small, while the power electronics' efficiency and reliability improve.