Robust Voltage Regulation of a DC–AC Inverter With Load Variations via a HDOBC Approach

In this brief, a harmonic disturbance observer (HDOB) based control approach is proposed for the robust voltage regulation design of a dc-ac inverter system. In distributed generation systems, wide range of load variations and effects of nonlinear loads result in significant degradations of control performance. Moreover, the loads, as the mismatched disturbances, impose adverse influences on the inverter system via a channel different from the control input. Toward that end, an HDOB is proposed to estimate the periodic load disturbances. By constructing new disturbance compensation gains, the effects of the mismatched periodic disturbances are removed from the output voltage channel. Rigorous stability analysis for the closed-loop system is presented. Experimental results are explored to illustrate the feasibility and capacity of the proposed control scheme.