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A pseudo direct drive (PDD) equipped with a coil-excited high-speed (HS) rotor is presented. An analytical model which predicts the flux density in the air spaces and the permanent magnets (PMs) of the PDD is presented, and it is shown that good agreement exists between the analytical and finite-element predictions. Furthermore, the model is employed to investigate the effects of the key design parameters on the performance of a coil-excited PDD for a 10-MW wind turbine application, and an optimized design is proposed. It is shown that shear stress in excess of 100 kPa can be achieved, and that compared with a PM-excited PDD, a reduction in PM mass can be realized. It is also shown that the efficiency over the operating range of the wind turbine can be maximized by adopting an appropriate control strategy of the HS rotor excitation currents. [ABSTRACT FROM AUTHOR]

This paper investigates the influence of pole number and stator outer diameter on the performance of superconducting (SC) generators. The SC generator has an iron-cored rotor topology. First, the generator structure is introduced and the optimization procedure is described. Then, the influence of design parameters on performance, in terms of generator volume, weight, SC wire utilization, active material cost, etc., is presented. Some relationships for the optimal combinations for different performance attributes are established. In addition, the influence of SC material price on the determination of optimal stator outer diameter and pole number is discussed. Finally, the influence of SC coil area per pole on performance is also investigated. [ABSTRACT FROM PUBLISHER]