Sub-Module Level Differential Power Processing for Parallel-Connected Architecture in Photovoltaic Systems

The partial shading on parallel-connected photovoltaic (PV) modules introduces severe mismatch issues in PV systems, which significantly affects the overall output power. Distributed maximum power point tracking (DMPPT) is considered as an effective solution to the resultant mismatch in parallel-connected PV sub-modules. In this context, this paper proposes a sub-module level switched-inductor (SL) based differential power processing (DPP) technique for parallel connections to alleviate the mismatch effect. The technique can achieve the maximum output power under mismatch by equalizing the sub-module voltages. The proposed technique is analyzed and compared through simulations with a traditional (Schottky diode) bypassing technique.