In a wind energy conversion system (WECS), changing the pitch angle of the
wind turbine blades is a typical practice to regulate the electrical power
generation in the full-load regime. Due to the turbulent nature of the wind and
the large variations of the mean wind speed during the day, the rotary elements
of the WECS are subjected to significant mechanical stresses and fatigue,
resulting in conceivably mechanical failures and higher maintenance costs.
Consequently, it is imperative to design a control system capable of handling
continuous wind changes. In this work, Linear Parameter Varying (LPV) H_inf
controller is used to cope with wind variations and turbulent winds with a
turbulence intensity greater than 10%. The proposed controller is designed to
regulate the rotational rotor speed and generator torque, thus, regulating the
output power via pitch angle manipulations. In addition, a PI-Fuzzy control
system is designed to be compared with the proposed control system. The
closed-loop simulations of both controllers established the robustness and
stability of the suggested LPV controller under large wind velocity variations,
with minute power fluctuations compared to the PI-Fuzzy controller. The results
show that in the presence of turbulent wind speed variations, the proposed LPV
controller achieves improved transient and steady-state performance along with
reduced mechanical loads in the above-rated wind speed region.Comment: 12 pages, 10 figure