Adaptive Impedance Shaping Method for Improving LCL-type GCI under Weak Grid

Abstract

LCL filter has been widely used to improve power quality for grid connected inverter(GCI) system. However, it brings stability problem under weak grid condition. This paper proposes a new series-connected adaptive stabilizer to address the problem in a different way. It only contains a current control loop without any PLL control which is easily implemented in reality. Experimental result reveals the correctness of proposed method.