Robust Tuning of Grid-Forming Converters Using Kharitonov Theorem

This paper presents a study on the robust tuning of damping coefficient, inertia, and conventional controller gains for a grid-forming converter connected to the main grid. The proposed method is evaluated using the Typhoon Hill system, which allows for comprehensive simulation and analysis. The Kharitonov theorem is utilized to achieve robustness in the face of deviations in line parameters. Unlike previous works, our approach systematically and graphically searches for a non-conservative Kharitonov region in the solution area of the controller coefficients. This region characterizes all stabilizing gain controllers that effectively stabilize an uncertain control structure. By selecting coefficients from the obtained non-conservative Kharitonov region, the synthesized controller effectively stabilizes the grid-forming converter. The results of this study highlight the efficacy of the Kharitonov theorem in achieving robust tuning of essential parameters for grid-forming converters, enhancing stability and performance in the presence of line parameter variations.