Back-to-back converter design and control for synchronous generator-based wind turbines

We present a step-by-step method for the design and control of a full-scale back-to-back converter for wind energy conversion systems using direct-drive electrically excited synchronous generators. First the system modeling is described in details. Then the converter controllers are designed and their PI parameters are systematically calculated using the symmetrical optimum method. Finally, the performances of a 2 MW class generator connected to the grid through the obtained converter are evaluated through simulations.