This paper presents a computational model of a microinverter for a single-phase grid-connected photovoltaic (PV) system. The microinverter is formed by a flyback converter with active-clamp, a voltage multiplier circuit, and a dual-buck inverter. The active clamp recycles the energy stored in the leakage inductance of the transformer and reduces the voltage stress in the MOSFET. The voltage multiplier helps to reach the DC voltage level required by the dual-buck inverter to inject current to the grid. This paper provides a description of the microinverter's hardware as well as the calculations used by the flyback and dual-buck controllers, which can be implemented in different simulation software. Experimental results show the capacity of the computational model to reproduce the electrical behavior of the microinverter operating in maximum power point tracking mode and injecting power to the grid.