A Novel Current Control Method for Grid Connected Photovoltaic System

A novel current control method based on improved repetitive control (RC) and fuzzy reasoning immune feedback for single-stage single-phase grid-connected (SSSPGC) photovoltaic (PV) system is proposed. Low-pass filter with zero-phase-shift is employed for delay part of RC to make better tradeoff between robustness and performance. Then the compensation part based on linear lead compensation function and a low-pass filter is designed so that the control method could be independent on the precise model of the plant. At last, an immune feedback controller based on fuzzy reasoning is presented to assure suitable amount of stability margin and better dynamic performance. A prototype of SSSPGC PV system is developed, and experimental results of the prototype under steady-state conditions verify the correctness and effectiveness of the proposed current control method.