Extended modeling for wind turbines with application to hybrid renewable energy systems

In the existing wind turbine benchmark models, generators are usually represented as a simplified first-order inertia model, which does not meet practical engineering scenarios. Moreover, fluctuations in machine parameters always exist in complex engineering environments which are not fully considered in the existing models. Motivated by the above, it is of significance to develop a wind turbine model capable of describing more practical situations. In this paper, a nonlinear extended wind turbine model is established which is further applied to a hybrid energy storage and hydrogen production system. Specifically, a comprehensive nonlinear extended model is proposed where ultra-local models are used to redesign control strategies for both machine side and grid side. A super-helical integral sliding-mode-observer is designed to estimate rotational speed and electrical angle in the presence of machine parameter mismatches and disturbances, so that the robustness of the model is enhanced. The wind turbine model is applied to a hybrid energy storage and hydrogen production system, serving as the supply side, which ensures stable power delivery based on control strategies for both machine side and grid side. The effectiveness of the proposed methods is demonstrated through co-simulation studies using MATLAB/SIMULINK and FAST and hardware-in-loop experimental platform.