Abstract:

Variable speed cascaded doubly fed induction generators (CDFIG) named also double stator induction generators (DSIG) or doubly fed twin stator induction generators (DFTSIG) or also brushless doubly-fed induction generator (BDFIG) can be an attractive alternative to conventional double output wound rotor induction generators. Cascaded doubly fed induction generator (CDFIG) examined in the paper consists of two identical wound rotor induction machines having their rotors mechanically and electrically coupled. The system employs two cascaded induction machines to eliminate the brushes and copper rings in the traditional DFIG. In this case, Cascaded induction generators require lower maintenance. In BDFIG both stators of connected machines are accessible. The control strategy for flexible power flow control is developed. The independent control of the active and reactive power flows is achieved by means of a tow quadrant power converter under the closed-loop stator flux oriented control scheme. The MATLAB simulation software is used for a preliminary investigation of BDFIG.

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