Finite-Time Command Filtered Backstepping Algorithm-Based Pitch Angle Tracking Control for Wind Turbine Hydraulic Pitch Systems

In this paper, a novel finite-time command filtered backstepping control algorithm is proposed to address the problems of high order nonlinearity, noise and friction interference when tracking the pitch angles of wind turbine hydraulic pitch systems. Since taking derivative is not required, the system noise cannot be amplified in the algorithm design process. The finite-time command filter is first employed to filter the state variables of the hydraulic pitch systems to eliminate the interference caused by the noise and friction. Moreover, the filter is combined with backstepping design to approximate the derivatives of virtual control variables to avoid “Differential expansion” phenomenon. In addition, in order to ensure the accuracy of the filtered signals to approximate the virtual control variables, a finite-time error compensation mechanism is designed. Simulation results show the effectiveness and high-precision tracking performance of the proposed algorithm in this paper.