A Comprehensive SoC-based Energy Management of a PV-BESS Microgrid

This paper deals with a state of charge (SoC)-based energy management of a microgrid (MG), which consists of a voltage source inverter (VSI), solar photovoltaic (PV) array, a battery energy storage system (BESS), and loads. As the MG is operated in grid connected (GC) and islanded (IS) modes, a simple sequential matching of magnitude and phase of load voltage to that of the grid is employed during the transition from IS to GC mode. An instantaneous seamless transition from GC to IS mode under grid fault conditions is developed. In GC mode, the VSI operates in current control, a boost converter (BC) operates solar PV array at maximum power point tracking (MPPT), and a bidirectional converter (BDC) controls the charging of BESS depending on the condition of its state of charge (SoC). In IS mode, the VSI operates in voltage control, the BDC regulates the DC-link voltage of VSI, and the BC operates the solar PV array in MPPT/voltage regulation mode based on SoC and load condition. The developed energy management offers comprehensive control of the MG ensuring continual supply to the loads under dynamic changes in irradiation and load changes. The effectiveness of the proposed control is tested using MATLAB/Simulink environment.