Designing of an On-Grid and Off-Grid PV System with Battery

This paper presents a control methodology for small power Photovoltaic (PV) system which can work off-grid and on-grid considering the amount of household energy consumption. The system components are 20 PV panels with 250 W and 8 batteries with 55 Ah. In this study, the design of the PV system is not like classic off-grid or on-grid PV systems. It depends on the grid up to the minimum level due to the different operating characteristics at four different periods of a day. The required capacities of the batteries are also maintained at a minimum level through an improved control method. The control unit of the system measures the consumption of the loads, the charge level of the batteries, and the grid constantly. So, the batteries are being charged only for a few hours in the morning and they are only being discharged in the evening peak hours. This control unit provides energy management. The Fuzzy logic is implemented to improve the performance of the control unit. As the result, the system cost and payback period are reduced with this approach. It is possible to provide more successful system management according to the classic control method.