Control of high performance single phase DC-AC inverter

Abstract

This thesis presents two digital repetitive control schemes for tracking output voltage of a single-phase DC-AC inverter. The proposed controller consists of a deadbeat controller and a plug-in repetitive controller, which is either time domain based (TDRC) or frequency domain based (FDRC). An important merit of the proposed repetitive control scheme is that they can be designed without detailed knowledge of the plant model. However, amongst the two repetitive approaches, FDRC provides improved tracking performance. The updating law of FDRC is designed by using Fourier series approximation. It gives freedom of choosing different learning gains individually for each harmonic component. Moreover, the time delay introduced due to filters can be compensated for each harmonic component to be eliminated. Experimental results show significant performance improvements of both TDRC and FDRC as compared to the conventional cascaded deadbeat controller, as well as the superiority of disturbance rejection of the FDRC scheme.