In this paper, two approaches based on sliding mode control for controlling a single-stage grid-connected three-phase solar photovoltaic system have been presented. The sliding mode control is robust and has good disturbance rejection as compared to the conventional proportional-integral control. Another advantage is that feedback linearization is not required for controlling nonlinear systems. There are two controlled variables namely the dc-link voltage and the q-axis component of the line current of the Voltage Source Converter. In the first approach, twisting controller and first order sliding mode controller have been used. Super twisting controller has been used to control both the variables in the second approach. The propsed control scheme has been simulated to verify the results. © 2015 IEEE.