This paper presents a three-port DC-DC converter for photovoltaic (PV)/battery stand-alone systems. The converter is designed by an effective combination of quadratic boost converter and a bidirectional port with low number of components. The converter performance consists of four operation modes with similar voltage gains, which improve reliability of the converter in comparison with the reviewed converters. Battery-alone mode is performed in the proposed configuration for the times input power of PV is equal to zero. Main advantages of the converter include its common grounded ports, operation with high voltage gain, current continuous of the input ports, utilizing low number of switch to perform four essential operation modes, and its high-efficiency performance due to low number of used components. Three switches of the structure enable it to control input power of main source and output voltage with two duty cycles per the modes. This number of switches in a three-port converter requires simpler driving and control systems in comparison with some of the previous presented three-port converters. The converter is analyzed, and its main equations are obtained. To validate feasibility of the converter and investigate coordination of its performance with theory, a prototype is prepared for 120 W output power.
