A Novel Repetitive Control Scheme for Grid-Tied Inverters in Consumer Electronics

To address the performance degradation of repetitive control (RC) under grid frequency fluctuations and improve transient performance in harmonic suppression, this paper proposes a novel plug-in proportional second-order feedforward dual-mode RC (SFDRC). The proposed SFDRC integrates a modified second-order dual-mode RC (SDRC) with feedforward channels and a proportional controller, significantly enhancing the dynamic performance and harmonic suppression capabilities. Compared to conventional RC method, the proposed SFDRC achieves higher gains and broader resonance bandwidths at fundamental and harmonic frequencies, ensuring effective current harmonic suppression even under grid frequency variations. A comprehensive parameter design methodology is provided based on a system model that incorporates a 1.5-cycle delay. Experimental validation on a 1.5-kW grid-tied inverter platform demonstrates the superior performance of the SFDRC, confirming its practical applicability and effectiveness in improving the performance of grid-tied systems.