Resilient Power Control of a Three-Phase Grid-Connected Inverter in the Presence of Uncertain Grid Impedance

Typically, unknown grid impedance in power distribution networks cannot be avoided; therefore, building an effective controller is essential. Furthermore, it is impossible to eliminate the intrinsic parameter uncertainty of the inverter filter. In this study, an AC power grid receives well-regulated power from a DC source using a systematic control method to address these problems. This work proposes a robust optimum control methodology based on linear matrix inequality (LMI) to ensure the stability of the inverter system while minimizing offset error at the output side. The LMI problem is solved by including the uncertainty of the grid impedance and filter parameter, thereby minimizing the convergence time to steady state. In addition to comparing performance under uncertain parameters, the simulation analysis of this proposed control compares vast and narrow uncertainty ranges.