Observer-based method for reduction of dc-link voltage ripple in two-stage boost inverters

This paper presents a control design method for reduction of dc-link voltage ripple in a two-stage boost inverter. The ripple reduction is achieved by using the harmonics of the dc-link voltage for feedback control of the dc-dc boost converter. The harmonics of the dc-link voltage are extracted by using a simple observer for linear systems. This observer based control was successfully implemented in experimental systems, where the ripple was reduced to about one third of the original magnitude. Robustness of the control algorithm was validated under different operating conditions.