DFIG equivalent circuit and mismatch assessment between manufacturer and experimental power-wind speed curves

The modelling of wind turbines with doubly-fed induction generator (DFIG) requires consideration of overall aerodynamic, mechanic, electromagnetic and control aspects, even in the case of DFIG representation in steady-state conditions for energy production assessment. This paper firstly summarizes the background concepts for interpreting the characteristic curves of the DFIG. Then, it considers and illustrates the structure and use of a dedicated equivalent circuit based on the incorporation of an apparent resistance in the model. Furthermore, a new method for correcting the experimental data gathered from wind turbines in practical applications is proposed, in order to make these data comparable with the quantities indicated by the manufacturers in the power-wind speed curve of the wind turbines. Application examples are provided by using data of real DFIG machines.

► Interpretation of the characteristic curves and control modes of the DFIG. ► Definition of a simplified equivalent circuit of the DFIG with apparent resistance. ► Interpretation of the DFIG operation regions above and below the synchronous speed. ► New probability-based method for correcting the wind speed Experimental data. ► Assessment of the average wind turbine efficiency with corrected wind speed values.