Determination of the optimal battery capacity of a grid-connected photovoltaic system with power and frequency fluctuations consideration

Power and frequency fluctuations are main problems of a grid-connected photovoltaic (PV) system. To effectively remedy this problem, the appropriate size of battery should be installed into the PV system. The dynamic model of the photovoltaic system and battery are discussed in this paper. Additionally, the dependent structure of solar irradiance and ambient temperature are taken into account. The proposed algorithm begins with solar radiation-temperature model. Then, the output power can be calculated based on the PV dynamic model. The rest of the interconnected power system is modeled as a synchronous generator. The battery used in this analysis is lead-acid battery. The proposed algorithm has been tested with a constructed test system. Satisfactory results were obtained.