Repetitive control for grid connected inverters with LCL filter under stationary frame

摘要

Severe distortion will occur in the output current of inverter when grid voltage is unbalanced with harmonics contained. In this paper a scheme of repetitive control for three-phase grid-connected inverters with LCL filter under stationary frame is proposed. The THD of the injected grid current is decreased obviously with the proposed scheme. Two separate decoupled control systems can be achieved when the mathematical model of grid-connected inverter with LCL filter is under stationary frame, hence complex decoupling process is not needed. According to actual hardware parameters, repetitive controller can be designed. Experimental results verify the correctness of the theoretical analysis and the feasibility of the proposed control strategy.