Abstract This study presents a control system for a single-phase DC/AC inverter operating in a microgrid with the capability of operating in both grid-connected and islanded mode with no need to reconfigure the control system which offers seamless transition between different modes. In this control scheme, in the grid-connected mode, the adopted control system emerges as an active-reactive power controller, while in the islanded mode; it inherently alters in order to form a microgrid with controlled voltage and frequency. As the control system is the same in both modes, the seamless transition is provided as a result. Moreover, the proposed control system is not reliant on synchronization of DC/AC inverter with the main grid which provides an effective solution for the case in which no communication system is intended or the DC/AC inverter and microgrid point of common coupling (PCC) are far away from each other. The small signal modeling of the proposed controller is used to corroborate the stable operation of the proposed system. Simulation studies in MATLAB and experimental evaluations confirm the effectiveness of the proposed solution.