Small Signal Modeling and Analysis of Parallel Inverters Controlled by Robust Droop Controller

Robust droop controller belongs to the virtual synchronous machine family, which guarantees the accurate power sharing and an autonomous grid support for the inverters in parallel. In this paper, a precise small signal model of the parallel inverter system controlled by the robust droop controller is constructed. Problems such as the influence of the control and system parameters and system harmonic responses are analyzed based on eigenvalue evaluations. The results reveal the operation characteristics of the system and are further verified through simulations in PSCAD/EMTDC.