Abstract: To address the problems of non-linearity, uncertainty of system parameters and external disturbances in maximum power tracking of permanent magnet direct-drive wind turbine systems,a non-singular fast terminal sliding mode inversion control strategy based on a finite-time disturbance observer is proposed. For the speed tracking problem, the system parameter uncertainty and external disturbances are defined as set-total disturbances, which are compensated after fast and accurate estimation by the observer. The inverse control method is used to deal with the nonlinear system, and the virtual control law is designed in combination with the dynamic surface control, while the sliding mode control law is designed to improve the convergence speed and tracking accuracy of the system. The stability and effectiveness of the system are demonstrated by Lyapunov theory and simulation experiments.

Key words: permanent magnet direct drive generators, maximum power tracking, finite time interference observer, non-singular fast terminal sliding mode control