Design and optimization of the PV-virtual-bus differential power processing photovoltaic systems

Differential power processing (DPP) is a promising architecture to solve an issue caused by mismatch among PV modules. PV to non-isolated port bus (or PV to the virtual bus) is one of the topologies studied in DPP architecture that allows each DPP converters can achieve maximum power point tracking (MPPT) independently. The string current value does not have an effect on MPPT but relates to the power processed by DPP converter. Keep that each PV is operating at the maximum power point (MPP) while allowing the DPP converter handle the minimum amount of power is the optimal solution. In this paper, the relation between string current and the power processed by DPP converter will be discussed. Further, algorithm has been designed for finding the string current value make DPP converter process the minimum power, and the simulation results for three PV panels are shown.