PI CONTROL DESIGN AND PASSIVITY/STABILITY ANALYSIS FOR DFIG WIND SYSTEMS UNDER VECTOR CONTROL CONSTRAINTS

摘要

A new approach for the PI controller design of the most popular wind turbine system used, namely the doubly-fed induction generator (DFIG), is proposed. The controller design is developed in the standard vector control frame, which is extensively applied for induction machine regulation. In this paper, starting from the nonlinear DFIG model, we prove stability by using the system passivity properties which we effectively maintain on both the open- and closed-loop system by suitably selecting the controllers' structure. The stability analysis conducted constitutes the main contribution of this work, since it is given for first time in a complete and general form. Thus, the heuristic application of the vector control is verified by a theoretical proof of stability. Moreover, this analysis results in some interesting observations for the reactive power regulation. Simulation results confirm the theoretical analysis.