Modeling and Analysis of Harmonic Stability in an AC Power-Electronics-Based Power System

This paper addresses the harmonic stability caused by the interactions among the wideband control of power converters and passive components in an AC power-electronicsbased power system. The impedance-based analytical approach is employed and expanded to a meshed and balanced threephase network which is dominated by multiple current- and voltage- controlled inverters with LCL- and LC-filters. A method of deriving the impedance ratios for different inverters is proposed by means of the nodal admittance matrix, and thus the contribution of each inverter to the harmonic stability of the overall power system can be easily predicted through Nyquist diagrams. Time-domain simulations and experimental tests on a three-inverter-based power system are presented. The results validate the effectiveness of the theoretical approach.