Doubly Grounded Dual-Input Transformer-less Three-phase Inverter for PV-battery system

Traditional three-phase photovoltaic (PV) inverters have common mode leakage current and are highly susceptible to the influence of light intensity. In order to solve this problem, three-phase double-grounded PV inverter with integrated battery energy storage is proposed in this paper. The system consists of PV modules, energy storage units and three-phase bridge inverter. In order to maximize the use of solar energy, the perturbation observation method is used to realize the maximum power point tracking (MPPT) of PV modules, and the corresponding charging control strategy is proposed for the energy storage units based on the state of charge balance of the battery pack, which realizes the power flow of the system and meets the normal operation of the PV inverter under different lighting conditions. The feasibility of the proposed inverter and control strategy is verified through simulation.