Modeling and simulation of conventionally wired photovoltaic systems based on differential power processing SubMIC-enhanced PV modules

This paper describes a photovoltaic (PV) power system architecture based on standard wiring of series-connected PV modules, where each PV module includes differential power processing (DPP) submodule integrated converters (subMICs). Given the absence of additional wiring commonly used to allow DPP subMICs to exchange power among PV modules, mismatches in such conventionally wired subMIC-enhanced system may result in bypassed sections, which yields a model with discontinuous-hard-nonlinearities and complicates numerical simulations. The paper presents a simple and efficient solver for the conventionally wired subMIC-enhanced system. The approach is used to examine the mismatch mitigation performance of this architecture in selected utility-scale and residential systems. Although the mismatch mitigation performance is inferior compared to the fully wired DPP subMIC-enhanced system, it is shown that there are cases where the conventionally wired DPP systems offer some energy yield and hot-spot mitigation improvements. Energy yield improvements are more significant in partially shaded systems with multiple parallel strings of modules, and in systems affected by nonuniform aging.