The paper proposes a two-port model of the inverter leg as building block to simulate the various topologies of switched-mode DC/AC converters, overcoming the problems encountered with the usual switch-diode simulation approach while retaining the interaction between the AC and DC sides. The model has a simple transformer-like formulation, easy to implement in any circuit simulation environment, and allows the lossless behavior, the conduction losses and the switching losses to be separately modeled. Using the same set of few parameters, it can be implemented in three different versions, from the most general to the simplest one, to be selected according to the application and to the accuracy requirements. A simplified expression for the load of the DC source is also derived allowing ready determination of DC operating point that is crucial to the efficiency of non-conventional power sources. As design tool, the proposed model has proved to be accurate and effective in predicting the behavior of a system, as can be seen from the application example reported in the paper, and it is very useful to dimension the power devices heatsink. In research and education areas, it also help to give physical insight into the converter operation and design criteria.