Abstract:
Capturing of maximum power using wind energy conversion systems
(WECS) is one of the focused problems in constructing high efficient wind energy
source systems. In wind turbines with variable speed, maximum power can be
reached at the point called optimal tip speed ratio point. Traditional anemometers
are not effective in terms of accuracy of measured speed. Various methods are
suggested to precisely estimate wind speed. A genetic algorithm is one of the
proposed approaches to calculate wind speed accurately. However, its
implementation is hard due to many parameters in the input. The relationship
between the aerodynamic torque and wind speed gives us the opportunity to
receive information about wind speed using the observed value of the
aerodynamic torque. Several observers such as robust observers and sliding mode
observers are introduced, and in their design stage, the assumption about slowly
varying aerodynamic torque is made. In some cases, the fact of the proportionality
of the aerodynamic torque to the wind speed makes this assumption inappropriate
for a real system. Linear control methods are not satisfied to control WECSs due
to its nonlinear nature. Application of nonlinear control techniques can be
complicated and difficult in practice.