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Partial shading is a problem that affects solar systems not only in their efficiency, but also in its lifetime. As a solution, integrated converters enable mismatched modules to deliver their maximum power. Voltage Equalizers are a type of partial power processing integrated converters, which results in more efficiency. There are many types of voltage equalizers, divided in three different architectures and based in many topologies, i.e. buck-boost, flyback, switched capacitors and voltage multipliers. Thus, in this paper, a comparative analysis of these converters are made, considering reliability and working principle, which is explained through simulation results. At the conclusions are made, pointing which circuit may be the best choice for a voltage equalizer.

Partial shading has shown to be a common efficiency issue for photovoltaic arrays installations, whether for islanded or grid-tied systems. Current diverter appears as reasonable solution, but with the increasing of string order, the currents deviated difficult the sizing of inductors. Also, in this type of converter, a multilevel synchronized gate-driver is needed. In this work, an independently cell string current diverter is proposed. This configuration is based in the Non-Dissipative String Current Diverter, however, its inductors current achieve low values during partial shading, and does not need synchronism of its gate-drivers. Also, this configuration facilitates one local Maximum Power Point Tracking for each module, and enables the enhancement of efficiency with simple implementation. The simulation and experimental results are presented to give support to the theoretical development.