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Electrical Diagnosis Technique Using Differential Power Processing Converters for Photovoltaic Panels

Partial shading on a photovoltaic (PV) panel is well known to trigger not only significantly reduced power generation but also the occurrence of multiple maximum power points (MPPs). Various kinds of differential power processing (DPP) converters have been proposed and developed to address partial shading issues. Meanwhile, power generation of PV panels substantially decreases as panels deteriorate due to damage, and therefore, PV panels are desirably diagnosed for early detection of degradation and malfunctions. In recent years, autonomous electrical diagnosis techniques based on ac impedance measurement are considered as a promising solution, but conventional electrical diagnosis techniques require expensive instruments. This paper proposes a DPP converter as well as an electrical diagnosis technique using the DPP converter. The proposed DPP converter not only preclude the partial shading issues but also offer the electrical diagnosis capability based on ac impedance measurement. The operation analysis and experimental verification tests using a prototype of the proposed DPP converter were performed. The results demonstrated the improved power yield from partially shaded PV panels and the electrical diagnosis capability of the proposed DPP converter.