Current multi-loop control strategy for grid-connected inverter with LCL filter

Abstract

A new multi current loop control strategy for LCL grid connected inverter is proposed. Repetitive PI double loop strategy which uses the feedback form of grid side current, utilizes PI control to improve the dynamic performance of the system, Then, repetitive control outer loop is used to achieve the high-performance control of the grid current, suppress voltage fluctuation and nonlinear load effect on the grid current and track the baseband signal without static error control. And the capacitor current feedback LCL inverter system aims at suppressing the high frequency resonance of LCL output filter; Theoretical analysis and experimental results show that LCL type grid connected inverter with this method has the advantages of high accuracy, good dynamic performance and strong anti-interference ability.