Operating Mode and Coordinated Power Control for Photovoltaic Battery Hybrid System Using Cascaded Multilevel Inverter

In order to reduce the power fluctuation of photovoltaic(PV) system and alleviate the contradiction between power generation and electricity consumption in power system, this paper presents a single phase grid-connected PV system integrating batteries using cascaded multilevel inverter, and an operating method for all-day economic operation of the PV system is proposed, including power smooth mode, self-charging mode and night mode. The power smooth mode smooths PV power fluctuations and ensure the output power to meet the demand of power dispatching, the self-charging mode realizes the self-charging of PV system and improves the utilization of solar energy, the night mode alleviates the contradiction between power generation and electricity consumption in power system. Three control methods are proposed to implement the proposed three operating modes. The proposed operating mode is reasonable, and the power coordination control method is simple in structure and easy to accomplish. Finally, the operating mode and control method are verified by the RT-lab hardware in-loop experimental platform.