The main goal in controlling wave energy converters is to maximize energy absorption. This paper focuses on maximizing the energy absorbed by the wave, using a point absorber converter that only has one degree of freedom. The controller used in this paper is a developed fast terminal sliding mode controller, which provides effective results in maximizing the absorbed energy of wave energy converters considering their complex dynamics in the presence of parametric and structural uncertainties, external disturbances and non-exact mathematical descriptions. Due to the high convergence rate and high precision, on the one hand, and avoiding the singularity problem, on the other hand, the non-singular fast terminal sliding mode controller is provided here. In addition to reducing the chattering phenomenon, a new switching function is proposed. Additionally the proposed controller provides high amount of absorbed energy by spending less power take off force, which has been evaluated by the innovative quantitative criteria d. The simulation results also show an effective decrease in the convergence time and tracking error.