In this paper, a new robust hybrid controller (RHC) is proposed to regulate current, voltage and, as a result, power output of a three-phase grid connected PV system. The creative process of the proposed controller consists of two steps. First, an input-output linearization method is used to eliminate system nonlinearities. Then, a robust PI controller is designed to reach the desired control objective. The robustness of PI is guaranteed by Lyapunov stability theory. Also, a maximum power point tracking (MPPT) algorithm is provided to adjust the PV output voltage for extracting MPP under various atmospheric conditions. To evaluate the performance of the proposed controller, different system conditions such as standard, considering uncertainties and three-phase short-circuit fault, are simulated and the results are compared with a feedback linearization controller (FLC). The results show superiority of the performance and robustness of the designed RHC versus various uncertainties such as solar irradiation and ambient temperature.