Experimental Performance of MPPT Algorithm for Photovoltaic Sources subject to inhomogeneous insolation

Photovoltaic (PV) power system performance depends on local irradiance conditions. PV systems are sometimes subject to partial shading, which may produce a non ideal characteristic curve, presenting true and local power maxima in the P-l curve. Traditional Maximum Power Point Tracking (MPPT) algorithms can converge to local maximum, which is not the true MPP. In order to solve the problem, the paper investigates on the effects of non-uniform solar irradiance distribution on a PV source. A MPPT algorithm able to optimize the source instantaneous operating power under non uniform irradiance is proposed. The ability of the algorithm and its increased performance in respect to traditional algorithms are evaluated by means of experimental tests performed on a real PV power system.