Maximum power point tracking for wind power systems with an improved control and extremum seeking strategy

SUMMARY Designing an efficient and effective maximum power point tracking (MPPT) method is a vital yet challenging task for modern large-scale variable speed wind power systems. In this paper, an improved control and extremum seeking strategy is proposed to construct a novel MPPT scheme, and the merit of this scheme is twofold. On the one hand, a nonlinear speed tracking controller is developed on the basis of the dynamic model of wind turbines, which cannot only track a desired rotor speed trajectory but also provide the extremum seeking module with estimation of the varying rotor torque. On the other hand, an extremum seeking module blended with lookup-table module is designed on the basis of a novel hill climbing searching method, which is more efficient because of its online updating structure and independence of the measurement of wind speed and output power. For simulation validation, a 10-MW direct driven wind turbine is used as a benchmark to test the proposed strategy.