The advances in computing and communication technologies allow to connect inverters of energy generation systems in smart grids, to well control the power flows. Modeling tools would be helpful in the design of required new inverter topology. This paper presents a modeling technique, so called Power Oriented Graph, easy to use and to be implemented in Matlab-Simulink environment. This technique has been used for modeling a recently proposed soft-switching grid-connected DC/AC power converter for photovoltaic systems. Modifications in the structure of the DC/DC converter and in the control of the DC/AC converter for smart grid applications are proposed. Simulation results confirm the effectiveness of the presented models and the introduced improvements.