In this paper, a novel approach is presented for closed-loop control of the photovoltaic (PV) systems using Lyapunov based nonlinear controller. In spite of changes of irradiance level and temperature in a wide range, developed controller is able to stabilize PV system at the maximum power point (MPP). Considering that derivative of the PV power is employed as a feedback signal, reference value of the controller will be zero in different operational conditions and hence, designed controller has a single-loop structure. According to elimination of the reference calculation unit, provided controller enjoys fast dynamic response during environmental condition changes. Asymptotic stability of the proposed method is proved using Barbalat lemma in the whole operating range of the system. In order to evaluate efficiency of the designed nonlinear controller, it is simulated in MATLAB software. Also, experimental results are obtained using the TMS320F2810 digital signal processor (DSP). Finally, steady-state and dynamic responses of the proposed controller are compared with standard linear regulator.