Prioritizing power factor in power density assessments of doubly fed induction generator alternatives

Doubly fed induction generators (DFIGs) are one of the most common wind turbine generators. In this paper, it is shown that evaluating DFIG alternatives like rotor-tied DFIGs and brushless doubly fed machines (BDFMs) without proper power factor considerations, can lead to inaccurate power density estimations. Finite element analysis (FEA) models of selected DFIG alternatives designed in available literature sources, are simulated as grid connected machines. The significant variations of power output with grid side power factor of these machine are highlighted. This denotes the need for more nuanced evaluation of the power density of these machines, especially when considering grid code requirements. It is therefore proposed that the power densities of DFIG alternatives be obtained at conditions within permissible grid code conditions.