Power Flow Control for Quasi-Z Source Inverter with Battery based PV Power Generation System

This paper presents a new power interface applied in photovoltaic (PV) power generation system-quasi-Z source inverter (qZSI) with a battery. In this topology, a battery is directly connected with a capacitor of qZSI network for energy storage. First, the configuration of the new system is designed and its operating principle is analyzed. Owing to the battery, the generation system can generate the desired stable grid power even if the PV panel output energy varies. An energy management is proposed to control the system while taking into account battery safety. With the energy management, the system can regulate the power flow to secure the battery from over charging or over discharging. This study explores a whole control for the PV generation system, including Perturb and Observe (P&O) method for MPPT control of PV panel, the grid-injected power control, and energy management control for battery safety operating. Several cases are simulated in MATLAB to verify the proposed control strategies. The results demonstrate that the whole system can operate effectively and safely, due to the proposed energy management.