Variable Structure Model Reference Adaptive Control for Squirrel-Cage Induction Generator-Based Wind Energy Conversion Systems

Squirrel cage induction generator is a low cost and robust alternative for grid-connected variable speed wind energy conversion systems. For maximum power point tracking of these systems, conventional vector control strategies may face some difficulties such as: model parameter uncertainties, variable reference and cross-coupled disturbances. Adaptive controllers may offer good reliability and robustness against these issues, but the traditional model reference adaptive control has a slow response in the transient, for these reasons, in this work a variable structure model reference adaptive controller is applied, since it has a faster transient response. In order to test the proposed controller, it is compared to the conventional PI control and the model reference adaptive control through Matlab/Simulink simulations. Flux and torque are controlled by a cascaded loop-based vectorial strategy. The results suggest that adaptive controllers are the best in a parametric uncertainty scenery, and the variable structure model reference adaptive control presented a faster transient response.