Partial shading losses mitigation of a rooftop PV system with DC power optimizers based on operation and simulation-based evaluation

Abstract

Building-applied photovoltaic (PV) systems improve urban building energy efficiency but are vulnerable to partial shading (PS) from near obstructions. This causes electrical losses owing to mismatch as well as reduction in module surface’s irradiance. Module level power electronics (MLPE) can mitigate these electrical losses caused by PS.The evaluation of the effectiveness of MLPEs in mitigating mismatch losses serves as the primary basis for determining its application during the system-design stage. However, research regarding the effects of applying MLPE is lacking. Further, the studies lack comparisons with various general PV system types, such as inverter types and array configurations.Therefore, the purpose of this study is to evaluate the mismatch losses mitigation effect of the DC power optimizer (DCPO), one of MLPEs. A rooftop PV (RTPV) system with DCPOs is selected for this study, and PS and operational performance are analyzed for RTPV system. Then, comparative analysis for the performance of the mimic RTPV model and seven general PV models, which are modeled for array configurations and different inverter types, is conducted using the simulation software.We developed four PV models with a central inverter and two with a string inverter, each with different shaded module connections. The annual array yields of these models decreased by up to 3.23% than mimic RTPV model, except for the model with micro inverters categorized as MLPE, which only experienced a 0.3% decrease. In the mismatch, it is expected that the PV system with MLPE can improve performance compared to the without MLPE.