Uncertainties in load power demand and unpredictabilities associated with renewable energy sources pose challenges to current microgrids. The situation worsens when the maximum power generated by a Photovoltaic (PV) module exceeds the power demanded by the load. The excess power increases the voltage at the point of common coupling (PCC). This paper addresses the issue of DC-link voltage regulation using a standalone PV module for the scenario when PV output at maximum power point (MPP) exceeds load demands. In particular, the time-scale separation between the fast PV dynamics and the slow variations in weather (temperature and irradiance) conditions is exploited to devise a novel non-iterative control strategy with fast closed-loop dynamics. A disturbance-rejection based robust control framework is employed and the closed-loop voltage regulation and load disturbance rejection performances are compared for the constant current and the constant voltage modes of operation of a PV module. Simulation case studies are presented which examine effectiveness and robustness of controllers for voltage regulation at the PCC.