SHADING EFFECT ON MPPT PERFORMANCE IN A GRID CONNECTED 20 kWp PV SYSTEM

摘要

Within the Italian PV roof-top Programme, a 20 kWp generator has been installed in Torino on the fa?ade of the company for the management of waste materials (AMIAT). Due to the fa?ade azimuth (20° W) besides the distances among the floors, a partial shading effect occurs during morning periods from April to September. The shading effect determines an important decrease of the module available power. However the paper focuses on the MPPT performance of inverters, in the mentioned shading conditions, during which experimental data have been recorded. Due to the tracking algorithm, the MPPT efficiency decreases (also < 80%) and the DC signals have ripple with greater amplitude but frequency lower than the typical 100 Hz value. These increased ripples (≈30%) produce an overload operation for the capacitors and inductor of the DC-DC converter that performs the tracking. This repetitive condition can cause failure of the inverters.