Design and evaluation of a modular resonant switched capacitors equalizer for PV panels

A switched-capacitor based equalization scheme is proposed for overcoming the adverse effect of shaded panels in a serially connected PV array. The proposed solution is based on a modular approach, in which each two panels are connected to a resonant switched-capacitor converter. The distribution of currents and power extraction improvement have been derived and verified experimentally and design guidelines to meet desired power loss level requirements have been developed. The experimental equalizing module was designed for 185W PV panels and was found to boost the maximum available power by about 50% when interfaced with two serially connected PV panels under insolation ratios between 20% and 100%. The analytical, simulation and experimental results suggest that the proposed approach is effective in extracting all available power with relatively high efficiency.