Flux programmed hybrid mode operation of a doubly fed induction generator for wind power application

The efficiency of a DFIG for wind power applications can be improved by reconnecting it as a SQIG below some critical prime mover speed, thereby, allowing optimal flux programming at lower shaft torques. This paper proposes a control scheme for smooth transition between DFIG and SQIG modes of operation of the same machine around a fixed prime mover speed. Detailed simulation results are presented confirming the validity of the proposed scheme.