Coordinated Virtual Inertia Control of Grid-Connected Photovoltaic-Battery Energy Storage System Considering Power Reserve and Fluctuation Smoothing

The integration of renewable energy, including photovoltaic (PV) systems, into the power grid has led to a decreased system inertia, posing a threat to frequency stability. Virtual inertia control (VIC) has been required for renewable energy systems to support the grid frequency. For a PV system with support from battery energy storage system (BESS), there are two main challenges when realizing VIC, i.e., the power reserve of PV panel output power and the PV power fluctuation smoothing. This paper proposes a coordinated VIC (CVIC) for grid-connected PV-BESS considering power reserve and fluctuation smoothing. The PV system reserves part of its output by power reserve control (PRC) to increase inertia provision capability without dependency on large-capacity BESS. Meanwhile, the BESS is manipulated to smooth PV power fluctuations caused by maximum available power (MAP) tracking in PRC and caused by environmental uncertainties. Then, the stable and efficient CVIC of PV-BESS is realized. Simulation results show that the proposed method can effectively realize PV power reserve, smooth PV power fluctuations caused by uncertainties, and improve the grid frequency quality.