Command Filter Adaptive Power Capture Control Based on Fuzzy Rules Emulated Networks for Variable Speed Wind Turbines With Flexible Shaft

This paper considers the power capture control problem of variable-speed wind turbine (VSWT) systems with flexible shaft. The control objective is to optimize the capture of wind energy by tracking the desired power output. A novel command filter based adaptive power signal feedback (PSF) control method is proposed to design the PSF controller for the non-affine nonlinear VSWT systems with a two-mass model for which the parameters are totally unknown. A compensation dynamic with adaptable parameters is designed to compensate the errors caused by command filtering and the unknown control gains. The unavailable aerodynamic torque is approximated by introducing fuzzy rules emulated networks (FRENs) and estimations of the unknown parameters and their learning laws are established to derive the virtual and actual control laws. Meanwhile, it is proved that all the signals in the closed-loop system are uniformly ultimately bounded (UUB) via Lyapunov synthesis. Finally, the feasibility of the proposed controllers is demonstrated on a 5-MW variable-speed wind turbine.