A Grid-Connected PV-energy Storage System with Synchronous Generator Characteristics

The technology of the virtual synchronous generator can efficiently improve the distributed generator in term of the capability to support frequency and the compatibility with the main grid. However, inertia of synchronous generators (SGs) cannot be introduced into photovoltaics (PV) generation systems in the absence of energy buffers. In this paper, a PV-energy storage (ES) system capable of mimicking SGs is proposed. The topology, control schemes and small-signal analysis for performance are investigated. Moreover, the designed coordination control enables the inverter to cooperate with the ES device in the system. The proposed PV-ES system is verified with simulations.