Improved Dual-loop Control plus Repetitive Control for PWM Inverters

This paper presents the analysis and design of a multiple-loop feedback control scheme for single-phase voltage source inverters with a L-C filter. In the proposed control scheme, a PI regulator in the outer voltage loop and a P regulator in the inner current loop are incorporated, and a plug-in repetitive controller is adopted to improve steady-state performance. Load current feed-forward compensation is additional adopted to reach minimum steady state error. Through theoretical analysis, it can be proved that dual-loop controller realizes arbitrary pole placement and thus the design procedure is greatly simplified. The superiority of the control scheme is demonstrated both by simulations and experiments.