The Influence of Higher-order Disturbance Estimation on Wind Power Generation of WECS using SMC with Sensorless Wind Speed Estimation

Abstract

The increasing demand for environmentally friendly, renewable, and clean energy sources as a substitute to fossil fuels, which emit greenhouse gases, continues to rise. Nonetheless, extracting the maximum wind power through the wind energy conversion system (WECS) hinges on accurately measuring the generator's reference speed and the aerodynamic torque. This paper introduces an approach using an exponential disturbance estimator to extract the WECS's maximum power by estimating aerodynamic torque (Tₐ) and wind speed (v). Unlike most existing literature that assumes the behavior of the torque to change slowly, this paper offers a thorough investigation of the impact of fast‑varying aerodynamic torque on WECS's power harnessing using observer‑based super‑twisting sliding mode control (STSMC). Simulation results under reduced‑intensity, fast‑varying, and extremely fast‑varying wind speeds were evaluated for zero‑order (ZO), first‑order (FO), and second‑order (SO) Tₐ estimations. Although higher‑order estimations improved speed tracking and enhanced maximum power extraction by about 6.5% under extreme variations (from 182.15 kW to 193.92 kW), the ZO estimation performed nearly as well under fast‑changing and low‑intensity wind conditions (e.g., 151.87 kW vs 152.08 kW, and 6.86 kW vs 6.89 kW, respectively). The analysis concludes that for environments with non‑extreme wind fluctuations, the simpler ZO estimation may be preferable due to lower noise and computational demands.