In this paper, the nonlinear photovoltaic system is studied. In order to make full use of photovoltaic energy, it is necessary to maintain maximum power output under each condition. First, apply incremental conductance algorithm to get the desired voltage under various conditions. Then, a fixed-time nonsingular backstepping controller is be present to ensure that the photovoltaic output voltage follows the desired voltage to reach the maximum photovoltaic power point. Moreover, there is no nonsingular phenomenon and the upper bound of the convergence time is determined by the control parameters and does not follow the initial value of the system. Further, the control strategy is theoretically proved by the Lyapunov stability theory. Finally, the effectiveness and efficiency of the designed controller are verified by simulation experiments.