Hybrid Analytical-Numerical Calculation of Equivalent Circuit Parameters and Steady-State Performance of DFIG

This paper describes a new hybrid analytical-numerical calculation method for predicting the equivalent circuit parameters and the performance of doubly fed induction generators (DFIGs). In comparison to established analytical methods, the equivalent circuit parameters are determined by calculating magnetic field parameters like the air-gap flux density and the total flux linkage of the stator and the rotor winding from magnetostatic finite element method (FEM) calculations. The discrepancies between analytical assumptions and FEM calculations are considered in the postprocessing, particularly in the case of strong magnetic saturation in the iron core. The performance of DFIG can be iteratively predicted using the equivalent circuit. Finally, a comparison with a transient FEM simulation validates the hybrid analytical-numerical calculation method.