Feeding partial power into line capacitors for low cost and efficient MPPT of photovoltaic strings

In PV strings, a number of PV modules are connected in series where the same current passes over all of them. To allow the maximum power points of the PV modules to be tracked individually, DC/DC converter known as optimizers could be used to interface each PV module with string. Processing the entire PV power by the optimizers increases the cost and degrades the system efficiency. In this paper, a method is proposed to have partial processing of the PV power using DC/DC converters which feed their output into capacitors connected in the same string of the PV modules. To further decrease the system cost and improve the efficiency, more than one PV modules can feed their partial power into the same capacitor. As the number of PV modules that share the same capacitor increases, the system cost decreases further. The validity of the proposed method is verified through simulation studies and hardware experimentation.