New MPPT Sliding Mode Approach for Grid Connected PV System

In this paper, a new sliding mode approach is proposed to track the maximum power point of a photovoltaic system connected to utility grid. The duty cycle is generated automatically by the Maximum Power Point Tracking (MPPT) system. The photovoltaic array is connected to the alternative current grid via a three-phase three-level voltage source converter and a boost converter. The three phase voltage source converter converts the direct current link voltage to alternative current and keeps unity power factor. The voltage source converter is controlled with two control loops: the current control loop which regulates the active and reactive currents grid components and the DC link voltage control loop. The unity of the power factor is assured by setting the reactive current reference equal to zero. The simulations results demonstrate the performance of the proposed MPPT controller in presence of both changes in irradiance level and ambient temperature.