In recent years, the application of photovoltaic system has been increasingly popular, especially in remote areas, where power is not available or is too expensive to install. However, the PV generator’s cost is relatively high and has nonlinear dependent-irradiation volt-ampere characteristics which make it difficult to control if we need to obtain maximum power. In this paper, the operation of a PV system which comprises a PV generator, a buck converter and a DC motor-pump is thoroughly examined. The buck converter controls the solar array operating point in order to track maximum power point (MPP) by using a non linear control strategy based on feedback linearization. This technique is shown to be able to obtain a linear control of the PV system and can dramatically increase its dynamical performance