Multivariable Extremum Seeking Control for Power Maximization and PI Tuning of Wind Turbine System

Maximization of the power capture is an important issue for the turbines that are installed in low wind speed area. In order to achieve the Maximum Power Point Tracking (MPPT), a method for wind turbine operations regions 2 and 3 has been developed here based on Extremum Seeking Control (ESC) approach. The reference speed to the generator and the reference pitch angle to pitch control were generated via dither-modulation ESC scheme. In addition to using ESC for generating the desired reference trajectories, ESC is also used for tuning PI controllers in order to determine the optimal gain values that can achieve a better tracking. The purpose is to (i) ensure the stability of the system (ii) extract the maximum electrical power capture as well as reduce the mechanical loads to protect the turbine. Comparison between the performance of the system using ESC real-time optimization and Particle Swarm Optimization (PSO) has been carried out in this paper. Furthermore, in the inner control loop, the implementation of Indirect Field Orientation Control (IFOC) has been presented to decouple the currents of the generator.