Image-Based Differential Power Processing for Photovoltaic Microinverter

Partial shading is a serious problem limiting the efficiency of photovoltaic (PV) systems. Differential power processing (DPP) architectures have been proposed to mitigate mismatch power losses caused by partial shading. However, maximum power point tracking (MPPT) for DPP converters is still an area of research. Instead of employing heuristic techniques, the proposed method is deterministic that can uniquely determine the respective maximum power points (MPPs) for the DPP Converters relying on the PV mathematical model and provided incident irradiances. The irradiances of the submodules are estimated using captured images obtained by an optical camera. Unlike the existing methods in literature which either produce fast transient response or accurate steady state tracking, the proposed method provides both fast transient response and accurate steady state output without oscillations. Moreover, the proposed approach does not need communication between converters or current sensing for the MPPT. The effectiveness of the proposed method is validated both by Simulink simulations and experimentally.