Adaptive nonsingular terminal sliding mode control for variable speed wind turbine

Abstract

In recent years wind energy is becoming more popular among other renewable sources due to more advanced technologies. Reduction in the cost of wind energy requires more efficient technology which is able to extract optimum power form the wind. The main focus of this work is to design a new adaptive controller for a variable speed wind turbine (VSWT) for maximizing turbine's energy capture. The generator torque is considered as the control input and it depends on the optimal rotor speed which is derived from the effective wind speed. From aerodynamic torque and rotor speed the effective wind speed is derived by Modified Newton Rapshon (MNR). Initially the conventional sliding mode controller (SMC) is considered. The control performance of SMC is compared with proposed Adaptive Nonsingular Terminal Sliding Mode Control (ANTSMC) for different level of random disturbances and actuator offset. The main advantage of ANTSMC is robustness to input disturbances and parametric uncertainties of the turbine. Both the controllers are tested for a single mass mathematical wind turbine (WT) model and validated through different mean wind speed with various random disturbances and actuator offset. Validation results show that the proposed control strategy is effective in terms of better energy capture and robustness to disturbances.