Decentralized Coordination Control of Multiple Photovoltaic Sources for DC Bus Voltage Regulating and Power Sharing

DC microgrids provide a coordinated paradigm to facilitate the penetration of photovoltaic (PV) sources due to their direct current essence. Along with the sustained growth of PV penetration, there is an increasing demand on PV sources to participate in dc bus voltage regulating, especially in small-sized or islanded dc microgrids. This paper develops a decentralized coordination control strategy that applies V-I droop concept to cooperate multiple PV sources in a dc microgrid. The proposed method enables PV sources to regulate the dc bus voltage and share their output power in an expected proportion. Furthermore, the maximum power point tracking (MPPT) function is unified in the suggested control method with a dp/dv regulator, which means multiple PV sources can work in the MPPT mode when they are grid-connected or shift with load demands in an coordinated way while keeping the dc bus voltage without switching the control configuration. Hardware-in-loop tests for different scenarios are conducted to validate the feasibility and effectiveness of the proposed control strategy.