Improved On–Off Control for Electromagnetic Torque Ripple Minimization of Wind Energy Conversion System

The present work mainly aims to introduce an improved On–Off control of a renewable energy system based on wind energy. The On–Off control has largely proven its effectiveness through several theoretical studies. The advantage of such a command, which makes it so important, is its robustness with respect to the perturbations and uncertainties of the model. However, these performances are obtained at the cost of certain drawbacks: the appearance of the phenomenon of chattering caused by the discontinuous part of the control which can have a harmful effect on the wind turbine life, the system is subjected at all times to a high control in order to ensure its convergence towards the operating point. Among the solutions proposed to these problems, mention may be made of limit-band On–Off control which consists in replacing the switching function by an hysteresis function. The goal is to maximize wind power point tracking and reduce mechanical stress when wind speed is considered. The results obtained are compared with those provided by the improved On–Off control with sign function in which our method can ensure better dynamic behavior and reduce the torque ripples of the wind energy conversion system.