Small-Signal Analysis of Grid-Forming Vector Current Control

Grid-Forming Vector Current Control (GFVCC) is a novel control strategy that enables gridconnected converters to provide stiff voltage regulation, inertia emulation, and power sharing. It enhances conventional Phase-Locked Loop (PLL)-based vector current control by incorporating a special PLL tuning strategy and virtual admittance, thus enabling the grid-forming functionalities. Although previous studies have validated its technical feasibility, further analysis of its behavior and its tuning are necessary. This work first develops a comprehensive Differential-Algebraic Equation (DAE) model of GFVCC in the dq-domain. Subsequently, the DAEs are numerically linearized to perform small-signal analysis and uncover additional properties. Our findings are established through modal and parameter sensitivity analysis in a single machine, infinite bus setup.