Adaptive SMC based cascaded control of the grid-forming inverter

The grid-forming inverter (GFI) plays an indispensable role in the microgrid (MG). Thus, it is critical for a microgrid to control the GFI flexibly and accurately, because of its voltage-forming and frequency regulation capabilities. The conventional proportional integral (PI) control strategy is usually used to control the GFI. However, the conventional PI control strategy has a high output voltage total harmonic distortion (THD) and deteriorative performance under external disturbances, which results in several problems in system flexibility, reliability and stability. This paper proposed a novel adaptive sliding mode control (ASMC) based cascaded control of the GFI system, which involves an ASMC-based inner current loop and outer voltage loop, and shows some superior performances of low THD, fast dynamic tracking performance and good robustness. Both the MATLAB/SIMULINK-based simulation and StarSim Modelling Tech-based semi-physical experimental results were presented to validate a perspective: the control strategy proposed by this paper has a better performance than the conventional PI control strategy under transient and steady-state condition.