Harmonic disturbances observer based control for DC-AC inverter

Considering the load uncertainties in real applications, a novel harmonic disturbance observer based control (HDOBC) approach is proposed for single-phase DC-AC inverter system subject to load resistance disturbance, which acts via a different channel from control input. Differing from the existing methods, a novel harmonic disturbance observer (HDO) is proposed to estimate the load disturbance. Then by designing an appropriate disturbance compensation gain, the mismatched disturbance is counteracted from the output channel. A rigorous stability analysis is presented. Comparing with the traditional state feedback control, the proposed method obtains a better disturbance rejection ability. Simulation results demonstrate the effectiveness of proposed method in the presence of mismatched disturbances.