Direct MPPT Algorithm for PV Sources With Only Voltage Measurements

This paper presents a direct maximum power point tracking method, based on an easy and robust way of identifying the maximum power point (MPP) of a photovoltaic (PV) source that needs the measurement of the PV generator voltage only. The algorithm accurately detects the MPP and can rapidly track it in presence of irradiance variations, with no erratic behavior. An interface for a PV inverter that employs the proposed algorithm is described. The converter, called double capacitor interface (DCI), is designed to charge the dc link of the inverter and follow the MPP of the PV generator. Numerical simulations of the system operation, in different irradiance conditions, are discussed and evaluation of the tracking efficiency is reported. Finally, experimental results of a prototype breadboard built to test on the field the MPP tracking capability are presented.