Photovoltaic output power improvement applying DC-DC converters on submodule level

This paper investigates the output energy of power optimizers for partial shading conditions and introduces a novel concept for boosting output energy in such situations. A MATLAB/Simulink model on cell level is developed for comparing the output energy of the different circuits to the theoretical maximum. It is shown that for power optimizers even small amounts of shading reduce the output energy significantly. Based on these results, the so called submodule concept is introduced, which overcomes these drawbacks. By integrating ASICs into the PV modules, the number of series connected solar cells is decreased, while additional costs are kept low and high reliability is maintained. The submodule concept provides the largest output energy improvement for low amounts of shading. From an economic point of view this is the most important operating area, since the theoretical harvestable energy decreases with increasing shading. Therefore, the submodule concept is a good and economic solution for increasing the overall energy yield of PV installations.