Spiking-free disturbance observer-based fixed-time sliding mode control of maximum power extraction from wind turbine

This paper proposes a new spiking-free fixed-time disturbance observer (DO)-based sliding mode control (SMC) scheme of maximum power extraction for the wind turbine system. First, a fixed-time DO is developed by using uniform robust exact differentiator (URED). Then, an SMC scheme is proposed by using the estimation of fixed-time DO and designing a spiking-free function. The proposed spiking-free fixed-time DO-based SMC scheme exhibits three attractive features: first, compared with existing scheme, the proposed scheme can guarantee the fast convergent performance under different initial system conditions based on the design of fixed-time stability. Second, by designing a novel spiking-free function, the potential spiking problem of fixed-time DO that occurs when observer gain is high and initial estimate states and initial true states are not equal is avoided. Third, the control input of proposed SMC is continuous, thus the undesirable chatter of conventional SMC is avoided. Finally, the attractive features of proposed scheme are illustrated based on simulation.