Maximum power tracking in WECS (Wind energy conversion systems) via numerical and stochastic approaches

•The structure of a MPPT (maximum power point tracking) scheme is presented.•The scheme is divided into the optimization algorithm and the tracking controller.•The optimization algorithm is based on an online line search numerical algorithm.•The tracking controller is treating the aerodynamics torque as a loop disturbance.•The control technique is simulated with stochastic wind speed by Simulink and FAST.

This paper presents a complete design of a two-level control system to capture maximum power in wind energy conversion systems. The upper level of the proposed control system adopts a modified line search optimization algorithm to determine a setpoint for the wind turbine speed. The calculated speed setpoint corresponds to the maximum power point at given operating conditions. The speed setpoint is fed to a generalized predictive controller at the lower level of the control system. A different formulation, that treats the aerodynamic torque as a disturbance, is postulated to derive the control law. The objective is to accurately track the setpoint while keeping the control action free from unacceptably fast or frequent variations. Simulation results based on a realistic model of a 1.5 MW wind turbine confirm the superiority of the proposed control scheme to the conventional ones.