Comparative Study of Voltage Equalizing Circuits for Photovoltaic String

Abstract

Abstract Partial shading is one of the inevitable condition that photovoltaic (PV) strings encounter. When photovoltaic strings are partially shaded, numerous peaks appear on their power versus voltage (P-V) characteristic curve, significantly reducing their ability to deliver power. This paper presents, three power electronics topologies that permit voltage equalization by charge redistribution between the PV modules wired in series. Three popular topologies, namely; switched-capacitor (SC), Buck-boost switched capacitor (BBSC) and PWM with switched capacitor (SC-PWM) converters have been examined. Complete experimentation have been done using MATLAB/Simulink environment. A comparative analysis have been done under various shading conditions. The findings demonstrate that the converters under consideration can improve the performance of string under partial shading.