Distributed maximum power point tracker for additional energy harvesting during partial shading of PV system

This paper describes the application of the distributed maximum power point tracker (DMPPT) to increase the energy yield of the photovoltaic (PV) system during partial shadings. It compares the performance of PV modules fitted with the SPV 1020 DMPPT chip to the one without it. Experimental work is carried out using eight polycrystalline modules, mounted on a two-axis rotating tracker. The partial shading are introduced using acrylic plastic with various darkness levels. Measurements are made to determine the effectiveness of DMPPT during shading and non-shading conditions. It is shown that although DMPPT performs well during partial shading, it yield lesser power (compared with the bypass diode case) under normal irradiance. This is due to the continuous power loss caused by the internal operation of the circuit, as well as the conduction and switching losses of the power switches.