Design of integral terminal sliding mode controller for the hybrid AC/DC microgrids involving renewables and energy storage systems

Traditional power generation is in the midst of a major transformation, and renewable based microgrids are playing a key role in this energy structure transition. This paper investigates the design of a centralized nonlinear controller based on the integral terminal and fast integral terminal sliding mode control for hybrid AC/DC microgrid involving renewable distributed generator as a primary source, fuel cell (FC) as a secondary source, and battery-ultracapacitor as hybrid energy storage system (HESS). At first, the detailed mathematical model of the hybrid AC/DC microgrid is established. Then, the controller is designed with the main objective to ensure the constant DC and AC bus voltage during islanding and grid-connected mode. During grid-connected mode, the controller is capable of providing frequency support to the utility grid. After that, the asymptotic stability of the hybrid AC/DC microgrid is proved using Lyapunov stability criteria. Then, the performance and robustness of the proposed control approach are tested by simulating it on MATLAB/Simulink, and the results are compared with sliding mode controller and Lyapunov redesign. Finally, real-time hardware in the loop tests are conducted to validate the effectiveness of the proposed framework.