Control method for flyback based submodule integrated converter with differential power processing structure

This paper presents the differential power processing (DPP) with isolated-port of submodule integrated converters (subMICs) in order to improve energy capture in photovoltaic (PV) power system. The nearly voltage equalization control and flyback subMICs are selected, which are working in discontinuous conduction mode (DCM) with fixed duty ratio 0.5. The simulation is built on Matlab/Simulink. The performance comparison was conducted for various scenarios, which shows that the structure can distinctly mitigate the energy loss in PV system causing by mismatch between each panel. The control can allocate the working point of each submodule close to true maximum power point (MPP) and module-level efficiency is achieved up to 98% for 72-cell PV module having 3 substrings with solar irradiation of 100%, 50% and 25%, respectively.