DC and AC Voltage Investigation in Isolated and Grid-Connected Hybrid Microgrid

This paper investigates the impact of the grid connection on the DC and AC bus voltages of a microgrid (MG), which is composed of a photovoltaic (PV), a battery energy storage system (BESS), and a diesel generator (DG). The considered MG is able to connect to the local distribution grid. An incremental conductance algorithm is implemented for the maximum power point tracking (MPPT) of the PV modules. Proportional-integral control is used for the MPPT and DC bus voltage regulation through the bidirectional converter connected with a BESS. A three-level inverter controlled by the space vector pulse width modulation is proposed in this study and is connected through the LC filter to interface with the AC bus, DG, and main grid. Two scenarios are investigated for MG operation: isolated and grid-connected modes.