New approach for optimizing energy by adjusting the trade-off coefficient in wind turbines

Abstract

Background: As fossil fuels run out, more attention should be paid to renewable energies, among which wind energy is one of the best. Therefore, the optimization of its energetic efficiency in variable speed wind turbines is an important focus of this recent study. Methods: Based upon linearization, a trade-off between energy conversion maximization and minimization of damage caused by mechanical fatigue, the resulting energy produced by a wind turbine, is optimized. Mathematically, the objective is defined as a stochastic criterion, belonging to the class of linear quadratic regulator (LQR) optimal control problems. Results: A linear control law has been obtained using an LQR stochastic approach, and the optimal value for α has been calculated using a real-value genetic algorithm. The numerical simulations show a better efficiency for this method compared to other methods used thus far. They also present a better stability when the optimal trade-off coefficient is applied. Conclusions: The results demonstrate that the curves of the state variables and output variables for the different valves of α converge to zero, which shows that the design controller was fully able to reduce the effectiveness of the white noise. © 2013 Fakharzadeh J et al.